Oomycete diversity and ecology in declining alder stands in Switzerland

Oomycete diversity and ecology in declining alder stands in Switzerland | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Oomycete diversity and ecology in declining alder stands in Switzerland Mizeriene Goda, Vaidotas Lygis, Prospero Simone This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6029813/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 May, 2025 Read the published version in Microbial Ecology → Version 1 posted 10 You are reading this latest preprint version Abstract In this study we assessed the occurrence and diversity of four oomycete genera ( Phytophthora , Phytopythium , Pythium and Globisporangium ) in 13 declining alder ( Alnus glutinosa and A. incana ) stands in Switzerland. For this, we sampled and analysed soil from tree rhizosphere, water from streams and rivers along which the stands were located, and symptomatic alder bark. The overall isolation rate was 47.2%, with a total of 400 oomycete isolates recovered at all 13 sites. The highest incidence of oomycete isolates was in soil samples (baiting, 82.5% isolation rate), followed by water (baiting, 14.7%), and bark (direct isolation, 2.7%). Of all recovered oomycete isolates, 90.3% could be successfully assigned to a known species, for a total of 23 species identified, including both preferential saprotrophs and pathogens. Among all genera, Phytophthora was the most abundant with 273 isolates (75.6%), followed by Phytopythium , Pythium and Globisporangium . Oomycete species diversity showed a significant variation among substrates. Only one species – Phytophthora lacustris – was abundant in all substrates, while 16 species were restricted to a specific substrate, mainly soil. The rhizosphere of symptomatic alder trees harboured the most diverse oomycete community, highlighting once again the importance of soil as a reservoir for these microorganisms. Only two Phytophthora species were isolated from alder bark lesions, namely, P. ×alni , the known causal agent of alder decline, and P. lacustris . The low recovery rate of P. ×alni might be due to attempts to isolate it from old, inactive lesions, but may also suggest that alder decline might be caused by other oomycetes infecting the root system of the trees. Alnus bark lesions rhizosphere soil water isolation Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Oomycetes are filamentous, fungus-like microbial eukaryotes [ 1 ]. Thanks to their diverse lifestyles, pathogenicity and host range these microorganisms can be considered as one of the most successful groups of eukaryotes, which is globally distributed in almost all ecosystems on Earth [ 2 ]. Although oomycetes are functionally heterogeneous [ 3 ], many of them are severe pathogens of agricultural crops and forest trees [ 4 , 5 ], with a significant impact on the global food security [ 6 ]. Regarding tree health, the genera Phytophthora ( P. ), Pythium ( Py. ) and Phytopythium ( Pp. ) are particularly relevant. The genus Phytophthora includes more than 200 currently known species [ 7 ], many of them being plant pathogens [ 8 ] and representing a phytosanitary threat to forest ecosystems worldwide [ 9 ]. Pythium species are not only plant but also animal, algal or fungal pathogens, as well as saprophytes. Currently, this genus counts more than 140 species, occurring in a wide range of both aquatic and terrestrial habitats [ 10 ]. Over the years, the genus Pythium has been reclassified, and more recently, based on the phylogeny and the morphology of the sporangium, it has been subdivided into the four genera Ovatisporangium , Globisporangium , Elongisporangium and Pilasporangium [ 11 ]. The genus Phytopythium is relatively new and was previously assigned to Pythium sp. clade K [ 12 ]. Uzuhashi et al. [ 11 ] reclassified this genus as Ovatisporangium , and now Ovatisporangium and Phytopythium are considered as synonyms [ 13 ]. This genus consists of 26 species [ 14 ] found in various habitats [ 15 ], mainly as necrotrophic generalists [ 1 ]. The introduction rate of pathogenic oomycetes into Europe’s natural ecosystems has increased dramatically over the last few decades [ 16 ] and continues to rise. Since the early 1990’s, a severe decline of alder ( Alnus spp.) has been observed first in Britain and then across the entire continent [ 17 ]. The causal agent of this decline was found to be Phytophthora alni sensu lato , a previously unknown Phytophthora species [ 18 ]. Later, it was shown that P. alni s. l. consists of three species, namely the hybrid P. × alni , and its two parental species P. ×multiformis , and P. uniformis [ 19 ]. These three species differ in morphology, genetic background, virulence, and geographic distribution [ 20 ]. In Switzerland, alder dieback has been observed since the early 2000s, and P. alni s.l. was first officially isolated in 2008 from declining alders along the Reuss river [ 21 ]. In 2020, the isolates were re-analysed and definitively attributed to P. ×alni [ 22 ]. However, since then no comprehensive study has been carried out to investigate the diversity of Phytophthora species in declining alder stands, although black ( Alnus glutinosa ) and grey ( A. incana ) alders are ecologically important species in riparian ecosystems such as river and stream banks, and lake shores. Recently, Schoebel et al. [ 23 ] presented results of a study that investigated Phytophthora community composition in Swiss watercourses over the period 2012–2016. A total of 11 Phytophthora species were detected, but no conclusions could be drawn linking the Phytophthora species found to declining alders. In the present study, we aimed at answering the following two questions: i) what is the incidence and diversity of the oomycete species belonging to the genera Phytophthora , Pythium , Phytopythium ( Ovatisporangium ) and Globisporangium in declining alder stands in Switzerland, and ii) how do incidence and diversity of the isolated oomycetes vary across sampling sites and substrates (i.e., symptomatic bark, rhizosphere soil and water)? Materials and Methods Study sites Field sampling was conducted at 13 sites in Switzerland between April and September 2015 (Table 1). The sites were selected with the help of the local forest service at locations (196-840 m a.s.l.) where declining alders ( Alnus incana , A. glutinosa ) had been observed. They either consisted of mostly disturbed (management, cattle, hiking) stands along a watercourse (stream or river) or within a marshland (for examples see Fig. 1A and B). All sites were sampled only once, except for Rottenschwil and Orvin, which were sampled twice in different months (July and September) because of the presence of numerous declining trees. At each site, alder trees with symptoms of decline, such as bark lesions (bleeding cankers, tarry spots on the outer bark) along the stem or at the root collar, and crown thinning (Fig. 1C-E, [18]), were selected for sampling. A total of 56 alder trees (42 A. incana and 14 A. glutinosa ) were sampled (bark lesions and rhizosphere), ranging from one (Le Landeron and Würenlos) to 11 (Orvin) trees per site (Table 1). In Schwyzerbrugg, no trees were sampled because it was too difficult to access them. Thirty-six of the sampled alder trees (64.3%) had bleeding bark lesions on the main stem or at the root collar (11 A. glutinosa and 25 A. incana trees), 11 trees exhibited a thin crown with decline symptoms (one A. glutinosa and ten A. incana trees), and nine trees showed both crown decline and bleeding bark lesions (two A. glutinosa and seven A. incana trees). A total of 13 water samples were collected at 11 sites (two sites, Orvin and Rottenschwil, with two water samples). Oomycete sampling and isolation After removing the bark at the margin of a stem lesion with a sterile knife, from one single lesion 20-30 pieces of phloem tissue were taken using a sterilized Jamshidi needle (2 mm in diameter) and placed on a selective CARP+ medium [24] directly in the field. The Petri plates were then incubated in the laboratory at 22 °C in the dark and for two to 14 days examined for the presence of oomycete-like hyphae growing out of the samples. When such hyphae were observed, an agar plug from the margin of the colony was transferred with a sterile toothpick onto a new Petri plate containing carrot piece agar (CPA) medium [25] and incubated at 22 °C in the dark to obtain a pure culture. Soil sampling was performed following the protocol of Tedersoo et al. [26]. Briefly, soil (in total about 1 kg per tree) was sampled along the four cardinal points around a symptomatic tree at 0.5-1.0 m distance from the root collar and at a depth of 5-20 cm using a spade. In the laboratory, soil was sieved through a sieve (mesh size 2 mm) and kept cool until further processing. If a waterbody (river, lake or pond) with banks covered with A. glutinosa or A. incana trees was present at the sampling site, approximately 1.5 l of water with sediments has also been collected from that waterbody. The presence of oomycetes in the collected soil and water samples was assessed using the baiting method proposed by Werres et al . [27]. Briefly, three days after sampling at the latest, 200 ml of the sampled soil was put in a plastic container (15 cm x 15 cm x 4 cm) and covered with 400 ml of distilled water. Thereafter, four young, healthy rhododendron leaves were put on the water surface as baits. Similarly, 400 ml of water with sediments has been poured into a plastic container and baited with four young, healthy rhododendron leaves. The containers were then incubated for 16 h light period at 20 ºC and 8 h dark period at 15 ºC for maximum 10 days. For the isolation of oomycetes, five tissue samples (ca 3 mm x 3 mm in size) were cut from each symptomatic leaf (surface-sterilized) around the formed necrotic spots and placed on Petri plates with CPA medium. The plates were incubated at 22 °C in the dark and pure cultures were obtained as described above for phloem tissue samples [27]. DNA extraction To obtain pure mycelium for better DNA extraction, an agar plug removed from the margin of a growing pure culture was transferred to a new Petri plate containing liquid V8 medium [28]. The plates were then incubated for 5–7 days at 22 °C in the dark until they were ca. 80 % covered by the culture. The mycelium was harvested on a filter paper by filtration with a Büchner funnel and a vacuum pump. The collected mycelium was washed off the filter paper with sterile distilled water and placed in a freezer at -20 °C until the DNA extraction. After lyophilization, DNA was extracted using the DNeasy® Plant Mini kit or the DNeasy® 96 Plant Kit (Qiagen, 96 Hilden, Germany). PCR and sequencing Isolates were identified to species by sequencing part of the ribosomal ITS region. PCR amplification was conducted in a 20-µl reaction volume containing final concentrations of 2x Master mix (JumpStart™ RedTaq® Ready Mix (SigmaAldrich, Germany)), 0.625 µM of each ITS6 [29] and ITS4 [30] primers, and 1 µl template DNA. The target region was amplified by PCR using a Veriti™ Thermal Cycler (Applied Biosystems, Foster City, CA, USA). Amplification was performed with initial denaturation at 95 °C for 2 min, following by 35 cycles of denaturation: 95 °C for 30 s, annealing: 55 °C for 30 s, extension: 72 °C for 2 min, final extension: 72 °C for 10 min. The PCR products were purified using Illustra™ ExoProStar™ PCR and Sequence Reaction Clean-Up Kit (Sigma-Aldrich, Germany), according to the manufacturer’s instructions. For sequencing, BigDye™ Terminator v. 3.1 Cycle Sequencing Kit and BigDye™ x-Terminator Purification Kit (Applied Biosystems, Carlsbad, CA) were used according to manufacturer’s protocol. The sequencing was performed on an ABI 3130 or ABI 3730xl capillary sequencer (Applied Biosystems, USA). The obtained sequences were assembled and edited using the software CLC Main Workbench version 8.0 Beta 4 (Qiagen, Bioinformatics, Denmark). For species identification, sequences (~800 bp) were compared with publicly available sequences in the National Center for Biotechnology Information (NCBI; https://blast.ncbi.nlm.nih.gov/Blast.cgi) database with Blast algorithm. Two sequences were considered to belong to the same species if they showed at least 99 % similarity. Representative sequences of all identified species are available in the NCBI database (https://www.ncbi.nlm.nih.gov/) under the accession numbers PV082471 to PV082524 (for details see Table S1). Assessment of oomycete diversity Individual-based rarefaction of Hill numbers (D) [31] was used to estimate oomycete diversity across various sites and substrates. The diversity indicators are characterized by the order q , which determines the sensitivity of the index to rare or abundant species. The diversity order q =0 ( 0 D) represents species richness and shows the diversity of all species. The diversity order of q =1 ( 1 D) displays “typical” species and functions as Shannon Diversity. Finally, the diversity order of q =2 ( 2 D) represents Simpson diversity and shows the diversity of dominant species [32]. Interpolated/extrapolated curves were produced with the iNEXT package (v.3.0.0) [33] in RStudio v. 4.2.3 (RStudio PBC, Boston, USA). To investigate whether uneven sample sizes from different sites affect total oomycete species diversity, we produced interpolated/extrapolated curves using iNEXT based on sample coverage (hereinafter SC) data. The iNEXT package estimateD function was used to calculate the diversity estimates for the minimum sample size between sites, by excluding uninformative sites. To determine whether diversity differences between sites were statistically significant, the 95% confidence intervals were compared. Since visually comparing all confidence intervals was difficult, the significance of the differences in species diversity in water and soil among sites was also determined by calculating and comparing Shannon diversity indices between sites using Hutcheson's t -test [34]. Results Oomycete incidence A total of 400 oomycete ( Phytophthora , Pythium, Phytopythium and Globisporangium ) isolates were recovered from the three different substrates (bark, soil, water). The overall isolation rate was 47.2%, with oomycetes recovered at all 13 sites. The highest incidence of oomycetes was obtained from soil samples (330 isolates, 82.5% isolation rate), followed by water samples (59 isolates, 14.7% isolation rate), and bark samples (11 isolates, 2.7% isolation rate). Out of the 400 oomycete isolates, 361 (90.3%) could be successfully assigned to a known species, for a total of 23 identified species (Table 2). The remaining 39 isolates could not be unequivocally assigned to a specific oomycete species and were thus removed from further analyses. Among all genera, Phytophthora was the most abundant with 273 isolates (75.6%), followed by Phytopythium (79 isolates), Pythium (six isolates) and Globisporangium (three isolates) (Table 2). Oomycete diversity across sampling sites The highest oomycete diversity was observed in Eggenwil (ten species), Lauerz (nine species), Magadino (eight species), and Orvin and Rottenschwil (seven species each) (Table 3). On the other hand, the sites Le Landeron, Schwyzerbrugg, Steinerberg, Lignières and Oberglatt exhibited the lowest oomycete diversity with only one to two species isolated from each site (Table 3). Based on the incidence data generated from sampling units (i.e., same sample size across sites), the coverage-based rarefaction and extrapolation sampling curve indicates that the sampling effort in this study was sufficient to catch up to 85% of the expected oomycete diversity (Fig. 2). As stated above, Eggenwil had the highest observed species diversity, but based on rarefied and extrapolated estimates for 22 isolates, Magadino had the highest species richness ( 0 D – 8.19), as well as the highest estimations for the most common (together with Eggenwil: 1 D – 7.49 and 7.53, respectively) and most abundant ( 2 D – 7.10) species (Table 3). Seven of the 13 sites sampled had SC scores greater than 0.90, which allows a reliable estimation of oomycete diversity (Table 3). Phytophthora . Phytophthora isolates were recovered at all 13 sites and belonged to 13 different species spanning seven different ITS clades (Fig. 3; [7]). On average, three Phytophthora species were detected in each site. The highest diversity was observed at Magadino with a total of six species, most of which belonged to the ITS clade 6 (Fig. 3). Twelve out of 13 detected Phytophthora species (all except P. citrophthora ) were recovered from soil samples, five from water (including P. citrophthora ), and two from bark lesions ( P. × alni and P. lacustris ). Phytopythium . The genus Phytopythium was found at nine of the 13 sites and included seven known species (Table 2, Fig. 3). Rottenschwil showed the highest Phytopythium species diversity, with a total of four different species detected. All six detected Phytopythium species were recovered from soil samples, two from water, and none from bark lesions. Pythium and Globisporangium . Representatives of genera Pythium and Globisporangium were rarely detected at the sampled sites and were isolated exclusively from soil samples (Fig. 3). Oomycete diversity across different substrate types Oomycete species diversity and incidence showed a significant variation within and among substrates (Fig. 3). Only one species – P. lacustris – was present and abundant in all substrates, while 16 species were restricted to a specific substrate, mainly soil. The rhizosphere of symptomatic alder trees harboured the most diverse oomycete community, with a total of 22 known species (Table 2, Fig. 3). However, most of these species were rather rare and each was represented by less than 10 isolates. Typical species present in the rhizosphere of declining alder trees were P. plurivora , P. lacustris , Pp. litorale and Pp. citrinum (altogether they included 80.0% of the identified oomycete isolates recovered from soil). Based on 95% confidence intervals, significant differences were observed among some sites in oomycete diversity in the soil (Fig. S1). These differences were confirmed by a Hutcheson's t -test comparing Shannon diversity indices (Fig. 4A). The aquatic oomycete community included a total of seven known species (five Phytophthora and two Phytopythium species) (Table 2, Fig. 3). The most common species in the water samples were P. lacustris and P. plurivora (23 isolates each; altogether they comprised 83.6% of the identified oomycete isolates recovered from water). Although the overall incidence of both species was the same, the first was found at 6 sites whereas the latter only at four sites. Notably, P. citrophthora was found only in water samples. Four Phytophthora species ( P. lacustris , P. gallica , P. gonapodyides and P. plurivora ) and two Phytopythium species ( Pp. chamaehyphon and Pp. litorale ) were identified in both soil and water samples. The differences among sites in oomycete species diversity in water were not as marked as in the soil (Fig. S2, Fig. 4B), but the number of water samples analysed was considerably lower than that of soil samples. Finally, only two Phytophthora species were isolated from alder bark lesions, namely, P. ×alni , the causal agent of alder decline, and P. lacustris (Fig. 3). Discussion Oomycete abundance and diversity Oomycetes were found at all 13 sites sampled, with Phytophthora being the most abundant genus followed by Phytopythium . The other two investigated genera, Pythium and Globisporangium , were clearly less frequent. Among the three substrates analysed, soil yielded the highest number of isolates and species, highlighting once again its importance as a reservoir for these microorganisms (e.g., [35-37]). Previous surveys of terrestrial and aquatic oomycete communities occasionally showed higher species diversity in water bodies compared to tree rhizosphere or forest soils (e.g., [35]). According to Català et al. [35], water bodies, and rivers in particular, seem to concentrate the inoculum of oomycetes of large areas, especially after rainy periods when the inoculum is discharged into larger bodies of water as runoff. On the other hand, the success of oomycete recovery from one or another substrate may depend on other factors, including the detection technique applied (e.g., [38]). We found a higher oomycete species diversity, in particular of Phytophthora species, in the rhizosphere of declining alder stands compared to other studies carried out in Austria [39], Italy [40], Poland [41] and Turkey [42]. Bregant et al. [43] isolated a similar number (12) of Phytophthora species from the rhizosphere of declining A. glutinosa trees in Portugal, but only five of them were common to our study. Riit et al. [44] used a metagenomic approach for detection of oomycetes in the rhizosphere soil of declining alder trees across the Fennoscandian and Baltic countries and detected DNA of ten Phytophthora species and 28 Pythium species. These differences could be partially due to detection methods applied, but also to the influence of abiotic and biotic factors like sampling season, geographic location, and vegetation type (e.g., [45, 46]). The overall diversity of Phytophthora species in our water samples was similar to that reported in surveys conducted in other European countries (e.g. [39, 47, 48]), and in Australia [49]. Of the other oomycete genera, only two species of Phytopythium were isolated at low frequencies from water samples during the present study. This is quite surprising as most taxa of the families Pythiaceae and Peronosporaceae are dependent on aquatic environments and are usually abundantly recovered from natural water bodies (e.g., [48, 50, 51]). This low success of oomycete recovering from water samples may be explained (inter alia) by the fact that we used an ex-situ baiting method, while an in-situ baiting would probably have allowed capturing more species [38]. Bark lesions on Alnus species yielded the lowest number and diversity of oomycetes - we were able to isolate only two Phytophthora species. A lower incidence and diversity of Phytophthora species in the alder bark than in the soil was also reported in other studies (e.g., [52]) and may be due to several factors, including a suboptimal isolation method (in our case, direct plating of bark samples in the field) or occasional sampling of old lesions in which Phytophthora might not be active anymore. Insights into the ecology of the isolated oomycete species The genus Phytophthora Phytophthora plurivora, P. lacustris and P. gonapodyides were the most abundant species in the rhizosphere soil and water samples, all of which are widespread in natural and agricultural ecosystems. Phytophthora plurivora is an aggressive soil-borne plant pathogen with a broad host range and worldwide distribution, often associated with declining forest trees (e.g., [53]). The high incidence of P. plurivora in declining alder stands in Switzerland is in agreement with the results of previous studies conducted in Europe (e.g., [41-43, 54, 55]). Although the clade 6 member P. lacustris is usually regarded as a saprotroph or opportunistic plant pathogen, which is common in riparian ecosystems in Europe and North America [56-58], there is a growing concern about its involvement in the aetiology of tree diseases. O’Hanlon et al. [59] speculated that this species may be responsible for black alder decline in Northern Ireland. The pathogen was also found infecting this alder species in Portugal [60], as well as causing diseases in several other plant hosts in Europe [57]. In our study, P. lacustris , together with P. ×alni were the only oomycete species isolated from alder bark lesions. Given the predominance of P. lacustris in Swiss watercourses [23], its exact role in causing alder decline in Switzerland should be further investigated. The third most frequently isolated Phytophthora species in our study, P. gonapodyides , also belongs to ITS clade 6 and has been traditionally regarded as a weak parasite with saprophytic abilities, usually present in aquatic environments [61]. In Europe, this species was already associated with declining broadleaved trees [53]. However, although in North America P. gonapodyides is considered an important species involved in the etiology of native alder species dieback [56], its role in alder decline in Europe is still unclear. All the other ten Phytophthora species identified in our study were restricted to one or two sites and mostly present only in soil. Among them, seven species were already known to occur in Switzerland [23], whereas for P. heteromorpha , P. niederhauserii , and P. pseudocryptogea this is the first report for the country. Phytophthora heteromorpha was first described in Italy from riparian habitats and in inoculation experiments proved to be pathogenic on A. incana [62]. Phytophthora niederhauserii is a highly pathogenic polyphagous species associated with ornamentals, fruit trees and native plants, distributed worldwide, including Europe [63, 64]. Finally, P. pseudocryptogea is a species within the P. cryptogea species complex that was officially described in 2015 [65]. In Turkey, P. pseudocryptogea was recovered from the rhizosphere of declining oaks [66], whereas in Canada the species was reported to cause root rot on western white pine ( Pinus monticola ) in seed orchards [67]. In Italy, it was isolated from declining alder trees [68], which indicates its potential to be pathogenic on trees. The genera Phytopythium, Pythium and Globisporangium The rhizosphere soil of declining alders was found to host a diverse assemblage of species of the genera Phytopythium , Pythium , and Globisporangium , which, to our knowledge, had never been previously investigated in natural ecosystems in Switzerland. These genera are known to include numerous plant pathogens mainly of tree seedlings and herbaceous plants [11, 69]. In this study, two Phytopythium species, namely Pp. litorale and Pp. citrinum , were quite commonly isolated from rhizosphere soil of declining alders . Derviş et al. [70] speculated that Pp. litorale may be the causal agent of the severe decline of oriental plane in Turkey, while Polat et al. [71] associated it to a kiwifruit dieback. In several European countries, USA, and Vietnam, Pp. litorale was found in watercourses [39, 51, 59]. Phytopythium citrinum is known as a common inhabitant of aquatic and riparian ecosystems in Europe and North America [47, 51]. Also, it was isolated from the rhizosphere of declining black alder and pedunculate oak trees in Poland [55, 72]. In a recent study by Christova [47], both Pp. citrinum and Pp. litorale showed moderate to high potential to infect several woody plant species, as well as some perennial and herbaceous plants. For this reason, both organisms were determined as pathogens with a wide host range. The other five Phytopythium species detected in this study were less frequent and limited to a few sites. While Pp. vexans is widespread worldwide and shows pathogenicity towards economically important woody hosts to which it causes root rot, damping off, crown rot, stem rot, or patch canker (e.g., [64], and references therein), the published information on the ecology of Pp. montanum , Pp. chamaehyphon , and Pp. paucipapillatum , is rather scarce and does not refer to Alnus species. Similarly, neither of the two Pythium species found in the present study – Py. aquatile and Py. lutarium , and neither of the two Globisporangium species – G. heterothallicum and G. intermedium , were associated with alder previously. Conclusions Confirming previous studies in Europe and North America, our analyses revealed a diverse and abundant community of oomycetes in declining alder stands in Switzerland, in particular in the rhizosphere of symptomatic trees. The species recovered ranged from known saprotrophs or opportunistic plant pathogens to aggressive pathogens. Noteworthy, only two Phytophthora species were isolated from bark lesions on alders, namely, P. ×alni , the known causal agent of alder decline, and P. lacustris . Although this might be partially explained by the fact that not all sampled bark lesions were still active, it could also suggest that the observed alder decline might be due to pathogens acting only in the root system and/or abiotic stress factors. Future studies are needed to build up understanding of the ecological role of all oomycete species recovered in such ecosystems as well as their possible interactions with alder and a changing environment. Understanding how oomycete communities are assembled in stands (e.g. based on functional traits, [ 73 ]) with different health status would also help to further clarify their role in forest ecosystems. Declarations Supplementary Information The online version contains supplementary material available at ........... (the link may be added later, after acceptance). Acknowledgements We thank Tetyana Tsykun for her help in the field and Quirin Kupper and Esther Jung for their help in the laboratory. Author contributions SP and GM designed the study and conducted the field sampling. GM analysed the data and wrote the first draft of the manuscript. SP, GM and VL edited, reviewed, and approved the final version. Funding This work was supported by a Sciex-NMSch Fellowship (Project Code 14.035) for GM. Data availability Representative sequences of all identified species are available in the NCBI database (https://www.ncbi.nlm.nih.gov/) under the accession numbers PV082471 to PV082524. Ethics approval No approval was required. Competing interests The authors declare no competing interests. References Lamour KH, Win J, Kamoun S (2007) Oomycete genomics: new insights and future directions. FEMS Microbiol Lett 274:1–8. https://doi.org/10.1111/j.1574-6968.2007.00786.x Thines M (2014) Phylogeny and evolution of plant pathogenic oomycetes - a global overview. Eur J Plant Pathol 138:431–447. https://doi.org/10.1007/s10658-013-0366-5 Fiore-Donno AM, Bonkowski M (2021) Different community compositions between obligate and facultative oomycete plant parasites in a landscape-scale metabarcoding survey. Biol Fertil Soils 57:245–256. https://doi.org/10.1007/s00374-020-01519-z Derevnina L, Petre B, Kellner R, Dagdas YF, Sarowar MN, Giannakopoulou A et al (2016) Emerging oomycete threats to plants and animals. Philos Trans R Soc Lond B Biol Sci 371:20150459. https://doi.org/10.1098/rstb.2015.0459 Fawke S, Doumane M, Schornack S (2015) Oomycete Interactions with Plants: Infection Strategies and Resistance Principles. Microbiol Mol Biol Rev 79:263–280. https://doi.org/10.1128/MMBR.00010-15 Fones HN, Bebber DP, Chaloner TM, Kay WT, Steinberg G, Gurr SJ (2020) Threats to global food security from emerging fungal and oomycete crop pathogens. Nat Food 1:332–342. https://doi.org/10.1038/s43016-020-0075-0 Abad ZG, Burgess TI, Bourret T, Bensch K, Cacciola S, Scanu B, et al (2023). Phytophthora : taxonomic and phylogenetic revision of the genus. Stud Mycol 106:259–348. https://doi.org/10.3114/sim.2023.106.05 Boevink PC, Birch PRJ, Turnbull D, Whisson SC (2020) Devastating intimacy: the cell biology of plant– Phytophthora interactions. New Phytol 228:445–458. https://doi.org/10.1111/nph.16650 Keriö S, Daniels HA, Gómez-Gallego M, Tabima JF, Lenz RR, Søndreli KL et al (2020) From genomes to forest management – tackling invasive Phytophthora species in the era of genomics. Can J Plant Pathol 42:1–29. https://doi.org/10.1080/07060661.2019.1626910 Kageyama K (2014) Molecular taxonomy and its application to ecological studies of Pythium species. J Gen Plant Pathol 80:314–326. https://doi.org/10.1007/s10327-014-0526-2 Uzuhashi S, Tojo M, Kakishima M (2010) Phylogeny of the genus Pythium and description of new genera. Mycoscience 51:337–365. https://doi.org/10.1007/s10267-010-0046-7 Baten MdA, Asano T, Motohashi K, Ishiguro Y, Rahman MZ, Inaba S et al (2014) Phylogenetic relationships among Phytopythium species, and re-evaluation of Phytopythium fagopyri comb. nov., recovered from damped-off buckwheat seedlings in Japan. Mycol Prog 13:1003. https://doi.org/10.1007/s11557-014-1003-1 de Cock AWAM, Lodhi AM, Rintoul TL, Bala K, Robideau GP, Abad ZG et al (2015) Phytopythium : molecular phylogeny and systematics. Persoonia 34(1):25–39. https://doi.org/10.3767/003158515X685382 Lodhi AM, Shahzad S, Syed RN (2020) The Genus Phytopythium . In: Rai M, Abd-Elsalam KA, Ingle AP (eds) Pythium: Diagnosis, Diseases and Management, 1st edn. CRC Press, Boca Raton, pp 45-76. https://doi.org/10.1201/9780429296406 Baten MdA, Mingzhu L, Motohashi K, Ishiguro Y, Rahman MZ, Suga H, Kageyama K (2015) Two new species, Phytopythium iriomotense sp. nov. and P. aichiense sp. nov., isolated from river water and water purification sludge in Japan. Mycol Prog 14:2. https://doi.org/10.1007/s11557-015-1027-1 Santini A, Ghelardini L, De Pace C, Desprez-Loustau ML, Capretti P, Chandelier A et al (2013) Biogeographical patterns and determinants of invasion by forest pathogens in Europe. New Phytol 197:238–250. https://doi.org/10.1111/j.1469-8137.2012.04364.x Brasier CM, Rose J, Gibbs JN (1995) An unusual Phytophthora associated with widespread alder mortality in Britain. Plant Pathol 44:999–1007. https://doi.org/10.1111/j.1365-3059.1995.tb02658.x Streito JC (2003) Phytophthora disease of alder: identification and distribution. In: Gibbs JN, Van Dijk C, Webber JF (eds) Phytophthora disease of alder in Europe. Edinburgh, UK: Forestry Commission Bulletin No. 126:25–38 Husson C, Aguayo J, Revellin C, Frey P, Ioos R, Marçais B (2015) Evidence for homoploid speciation in Phytophthora alni supports taxonomic reclassification in this species complex. Fungal Genet Biol 77:12–21. https://doi.org/10.1016/j.fgb.2015.02.013 Marçais B (2018) Phytophthora alni species complex (alder Phytophthora ). Wallingford, UK: CABI Compendium 40948. https://doi.org/10.1079/cabicompendium.40948 Meier F, Engesser R, Forster B, Odermatt O, Angst A (2009) Forstschutz-Überblick 2008 [Forest protection overview 2008]. Birmensdorf: Eidgenössische Forschungsanstalt WSL, 24 p (In German). Mizeriene G, Cerny K, Zyka V, Bakonyi J, Nagy ZA, Oliva J, Redondo MA, Corcobado T, Prospero S (2020) Patterns of genetic diversification in the invasive hybrid plant pathogen Phytophthora× alni and its parental species P. uniformis . Phytopathology 110:1959–1969. https://doi.org/10.1094/PHYTO-12-19-0475-R Schoebel CN, Prospero S, Rigling D, Ruffner B (2024) Fishing for Phytophthora in watercourses of the highly urbanized Swiss Plateau. Mycol Prog 23:17. https://doi.org/10.1007/s11557-024-01951-7 Erwin DC, Ribeiro OK (1996) Phytophthora diseases worldwide. APS Press, St. Paul, MN. https://doi.org/10.1046/j.1365-3059.1998.0179a.x Werres S, Marwitz R, Man In't veld WA, De CockWAM, Bonants, PJM et al (2001) Phytophthora ramorum sp. nov., a new pathogen on Rhododendron and Viburnum. Mycol Res 105:1155–1165. https://doi.org/10.1017/S0953756201004865 Tedersoo L, Bahram M, Polme S, Koljalg U, Yorou S, Wardle DA, Lindahl BD (2014) Disentangling global soil fungal diversity. Science 346:1052–1053. https://doi.org/10.1126/science.aaa1185 Werres S, Hahn R, Themann K (1997) Application of different techniques to detect Phytophthora spp. in roots of commercially produced Chamaecyparis lawsoniana. Z Pflanzenkr Pflanzenschutz 104:474–482. Miller PM (1955) V-8 juice agar as a general purpose medium for fungi and bacteria. Phytopathology 45:461–462. Cooke DEL, Drenth A, Duncan JM, Wagels G, Brasier CM (2000) A molecular phylogeny of Phytophthora and related oomycetes. Fungal Genet Biol 30:17–32. https://doi.org/10.1006/fgbi.2000.1202 White TJ, Bruns T, Lee S, Taylor J (1990) Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, et al. (eds) PCR Protocols: A Guide to Methods and Applications. Academic Press, Inc., San Diego, USA; London, England, UK, pp 315–322. Jost L (2006) Entropy and diversity. Oikos 113:363–375. https://doi.org/10.1111/j.2006.0030-1299.14714.x Chao A, Gotelli NJ, Hsieh TC, Sander EL, Ma KH, Colwell RK, Ellison AM (2014) Rarefaction and extrapolation with Hill numbers: a framework for sampling and estimation in species diversity studies. Ecol Monogr 84:45–67. https://doi.org/10.1890/13-0133.1 Hsieh TC, Ma KH, Chao A (2016) iNEXT: an R package for rarefaction and extrapolation of species diversity (Hill numbers). Methods Ecol Evol 7:1451–1456. https://doi.org/10.1111/2041-210X.12613 Hutcheson K (1970) A Test for comparing diversities based on the Shannon formula. J Theor Biol 29: 151–154. https://doi.org/10.1016/0022-5193(70)90124-4 Català S, Pérez-Sierra A, Abad-Campos P (2015) The use of genus-specific amplicon pyrosequencing to assess Phytophthora species diversity using eDNA from soil and water in Northern Spain. PLoS ONE 10:e0119311. doi:10.1371/journal.pone.0119311 Jung T, La Spada F, Pane A, Aloi F, Evoli M, Horta Jung M et al (2019) Diversity and Distribution of Phytophthora Species in Protected Natural Areas in Sicily. Forests 10:259. https://doi.org/10.3390/f10030259 Jung T, Scanu B, Brasier CM, Webber J, Milenković I, Corcobado T et al (2020) A survey in natural forest ecosystems of Vietnam reveals high diversity of both new and described Phytophthora taxa including P. ramorum . Forests 11:93. https://doi.org/10.3390/f11010093 Pettitt TR (2023) Monitoring oomycetes in water: combinations of methodologies used to answer key monitoring questions. Front Hortic 2:1210535. https://doi.org/10.3389/fhort.2023.1210535 Corcobado T, Cech TL, Daxer A, Ďatková H, Janoušek J, Patra S et al (2023) Phytophthora , Nothophytophthora and Halophytophthora diversity in rivers, streams and riparian alder ecosystems of Central Europe. Mycol Prog 22:50. https://doi.org/10.1007/s11557-023-01898-1 Bregant C, Sanna GP, Bottos A, Maddau L, Montecchio L, Linaldeddu BT (2020) Diversity and Pathogenicity of Phytophthora Species Associated with Declining Alder Trees in Italy and Description of Phytophthora alpina sp. nov. Forests 11:848. https://doi.org/10.3390/f11080848 Trzewik A, Orlikowski LB, Oszako T, Nowakowska J, Orlikowska T (2015) The characterization of Phytophthora isolates obtained from diseased Alnus glutinosa in Poland. Balt For 21:44–50. Aday Kaya AG, Lehtijärvi A, Şaşmaz Y, Nowakowska JA, Oszako T, Doğmuş Lehtijärvi HT, Woodward S (2018). Phytophthora species detected in the rhizosphere of Alnus glutinosa stands in the floodplain forests of Western Turkey. For Pathol 48:e12470. https://doi.org/10.1111/efp.12470 Bregant C, Batista E, Hilário S, Linaldeddu BT, Alves A (2023) Phytophthora Species Involved in Alnus glutinosa Decline in Portugal. Pathogens 12:276. https://doi.org/10.3390/pathogens12020276 Riit T, Cleary M, Adamson K, Blomquist M, Burokienė D, Marčiulynienė D et al (2023) Oomycete Soil Diversity Associated with Betula and Alnus in Forests and Urban Settings in the Nordic–Baltic Region. J Fungi 9:926. https://doi.org/10.3390/jof9090926 Sarker SR, Burgess TI, Hardy GESJ, McComb J (2023a) Closing the gap between the number of Phytophthora species isolated through baiting a soil sample and the number revealed through metabarcoding. Mycol Prog 23:39. https://doi.org/10.1007/s11557-023-01892-7 Sarker SR, McComb J, Hardy GESJ, Burgess TI (2023b) Sample volume affects the number of Phytophthora and Phytopythium species detected by soil baiting. European J Plant Pathol 166:303–313. https://doi.org/10.1007/s10658-023-02661-8 Christova PK (2024) Fishing for estuarine oomycetes. Diversity 16:530. https://doi.org/10.3390/d16090530 Matsiakh I, Oszako T, Kramarets V, Nowakowska JA (2016) Phytophthora and Pythium species detected in rivers of the Polish-Ukrainian border areas. Balt For 22:230–238. Hüberli D, Hardy GESJ, White D, Williams N, Burgess TI (2013) Fishing for Phytophthora from Western Australia’s waterways: a distribution and diversity survey. Australas Plant Pathol 42:251–260. https://doi.org/10.1007/s13313-012-0195-6 El-Hissy FT (1994) Oomycetes and Chytridiomycetes ( Mastigomycotina ) from water bodies in Tübingen region (Germany). J Basic Microbiol 34:67–76. https://doi.org/10.1002/jobm.3620340202 Shrestha SK, Zhou Y, Lamour K (2013) Oomycetes baited from streams in Tennessee 2010–2012. Mycologia 105:1516–1523. https://doi.org/10.3852/13-010 Jung T, Blaschke M (2004) Phytophthora root and collar rot of alders in Bavaria: Distribution, modes of spread and possible management strategies. Plant Pathol 53:197–208. https://doi.org/10.1111/j.0032-0862.2004.00957.x Jung T, Pérez-Sierra A, Durán A, Horta Jung M, Balci Y, Scanu B (2018) Canker and decline diseases caused by soil- and airborne Phytophthora species in forests and woodlands. Persoonia 40:182–220. https://doi.org/10.3767/persoonia.2018.40.08 Černý K, Tomšovský M, Mrázková M, Strnadová V (2011) The present state of knowledge on Phytophthora spp. diversity in forest and ornamental woody plants in the Czech Republic. N Z J For Sci 41S:S75–S82. Tkaczyk M, Szmidla H, Sikora K (2023) Occurrence of Phytophthora species in the rhizosphere of dying black alder Alnus glutinosa in central and northeastern Poland. Sylwan 167:452−460. https://doi.org/10.26202/sylwan.2023040 Sims LL, Sutton W, Reeser P, Hansen EM (2015) The Phytophthora species assemblage and diversity in riparian alder ecosystems of western Oregon, USA. Mycologia 107:889–902. https://doi.org/10.3852/14-255 Nechwatal J, Bakonyi J, Cacciola SO, Cooke DEL, Jung T, Nagy ZÁ et al (2013) The morphology, behaviour and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov. Plant Pathol 62:355–369. https://doi.org/10.1111/j.1365-3059.2012.02638.x Bourret TB, Mehl HK, Aram K, Rizzo DM (2023) Rhododendron leaf baiting of coastal California watersheds for Phytophthora and Nothophytophthora . Mycol Prog 22:62. https://doi.org/10.1007/s11557-023-01910-8 O'Hanlon R, Wilson J, Cox D (2020) Investigations into Phytophthora dieback of alder along the river Lagan in Belfast, Northern Ireland. Irish Forestry 77:33–48. Kanoun-Boulé M, Vasconcelos T, Gaspar J, Vieira S, Dias-Ferreira C, Husson C (2016) Phytophthora ×alni and Phytophthora lacustris associated with common alder decline in Central Portugal. For Pathol 46:174–176. https://doi.org/10.1111/efp.12273 Brasier CM, Cooke DE, Duncan JM, Hansen EM (2003) Multiple new phenotypic taxa from trees and riparian ecosystems in Phytophthora gonapodyides–P. megasperma ITS Clade 6, which tend to be high-temperature tolerant and either inbreeding or sterile. Mycol Res 107:277–290. https://doi.org/10.1017/S095375620300738X Bregant C, Rossetto G, Sasso N, Montecchio L, Maddau L, Linaldeddu BT (2024) Diversity and distribution of Phytophthora species across different types of riparian vegetation in Italy with the description of Phytophthora heteromorpha sp. nov. Int J Syst Evol Microbiol 74:006272. https://doi.org/10.1099/ijsem.0.006272 Abad ZG, Abad JA, Cacciola SO, Pane A, Faedda R, Moralejo E et al (2014) Phytophthora niederhauserii sp. nov., a polyphagous species associated with ornamentals, fruit trees and native plants in 13 countries. Mycologia 106:431–447. https://doi.org/10.3852/12-119 Beluzán F, Miarnau X, Torguet L, Armengol J, Abad-Campos P (2022) Survey of oomycetes associated with root and crown rot of almond in Spain and pathogenicity of Phytophthora niederhauserii and Phytopythium vexans to ‘Garnem’ rootstock. Agriculture 12:294. https://doi.org/10.3390/agriculture12020294 Safaiefarahani B, Mostowfizadeh-Ghalamfarsa R, Hardy GEStJ, Burgess TI (2015) Re-evaluation of the Phytophthora cryptogea species complex and the description of a new species, Phytophthora pseudocryptogea sp. nov. Mycol Progress 14:108 https://doi.org/10.1007/s11557-015-1129-9 Kurbetli I, Woodward S, Aydoğdu M, Sülü G, Özben S (2022) Phytophthora plurivora and Phytophthora pseudocryptogea isolated from soils supporting declining oaks ( Quercus robur L.) in İstanbul, Turkey. For Path 52:e12782. https://doi.org/10.1111/efp.12782 Shamoun SF, Feau N, Islam A, Ruff K, Drugmand B (2024) Survey of oomycetes and pathogenicity of Phytophthora cinnamomi associated with root rot disease of western white pine ( Pinus monticola ). Can J Plant Pathol 46:648–660. https://doi.org/10.1080/07060661.2024.2383588 Seddaiu S, Linaldeddu BT (2020) First Report of Phytophthora acerina , P. plurivora , and P. pseudocryptogea Associated with Declining Common Alder Trees in Italy. Plant Dis 104:1874 https://doi.org/10.1094/PDIS-01-20-0186-PDN Hendrix FF, Campbell WA (1973) Pythiums as Plant Pathogens. Annu Rev Phytopathol 11:77–98. https://doi.org/10.1146/annurev.py.11.090173.000453 Derviş S, Türkölmez Ş, Çiftçi O, Özer G, Ulubaş Serçe Ç, Dikilitas M (2020) Phytopythium litorale : A Novel Killer Pathogen of Plane ( Platanus orientalis ) Causing Canker Stain and Root and Collar Rot. Plant Dis 104:2642–2648. https://doi.org/10.1094/PDIS-01-20-0141-RE Polat Z, Kaymak S, Gültekin MA, Bayraktar H, Özer G (2023) First report of Phytopythium litorale associated with dieback disease of kiwifruit in Turkey. J Plant Pathol 105:1761–1762. https://doi.org/10.1007/s42161-023-01510-1 Tkaczyk M (2020) Phytopythium : origin, differences and meaning in modern plant pathology. Folia For Pol Ser A For 62:227–232. https://doi.org/10.2478/ffp-2020-0022 Redondo MA, Boberg J, Stenlid J, Oliva J (2018) Contrasting distribution patterns between aquatic and terrestrial Phytophthora species along a climatic gradient are linked to functional traits. ISME J 12:2967–2980. https://doi.org/10.1038/s41396-018-0229-3 Tables Table 1 Information about the 13 sites sampled in this study and the number of samples collected. Site Coordinates (WGS84) Waterbody name (type) Sampled Alnus species Forest type Samples (N) Longitude Latitude Bark Soil Water Eggenwil 8.3384 47.36432 Reuss (river) A. incana Riparian 7 7 0 Lauerz 8.58025 47.03799 Chlausenbach (stream) A. glutinosa , A. incana Riparian 8 8 1 Le Landeron 7.05001 47.0499 Vieille Thielle (duct) A. glutinosa Riparian 1 1 1 Lignières 7.07807 47.09019 Unnamed (pond) A. glutinosa Riparian 4 4 1 Magadino 8.8694 46.15581 Ticino (river) A. incana Marsh 6 6 1 Nussbaumen 8.82237 47.61628 Nussbommersee (lake) A. incana Marsh 2 2 0 Oberglatt 8.51323 47.48062 Glatt (river) A. incana Marsh 2 2 1 Orvin 7.20246 47.15602 L’Orvine (river) A. glutinosa , A. incana Riparian 11 11 2 Rottenschwil 8.373 47.32264 Reuss (river) A. glutinosa , A. incana Riparian 10 10 2 Schwyzerbrugg 8.7123 47.15264 Biber (river) A. incana Riparian 0 0 1 Steinerberg 8.57789 47.04523 Goldbach (stream) A. incana Riparian 2 2 1 Wil 8.51377 47.61742 Schwarzbach (stream) A. glutinosa , A. incana Riparian 2 2 1 Würenlos 8.37022 47.43536 Limmat (river) A. glutinosa Riparian 1 1 1 Total 56 56 13 Table 2 Incidence of identified (i.e., assigned to known species) oomycete taxa recovered from three substrate types (soil, water and bark) sampled in declining alder (Alnus glutinosa and A. incana) stands in Switzerland (for more information see Materials and Methods section). Taxa Soil Water Bark Sites a Isolates b Sites Isolates Sites Isolates P. citrophthora 0 - c 1 3 (5.80) 0 - P. plurivora 6 113 (53.80) 4 23 (44.20) 0 - P. pseudosyringae 1 1 (0.48) 0 - 0 - P. bilorbang 1 3 (1.43) 0 - 0 - P. chlamydospora 1 2 (0.95) 0 - 0 - P. gonapodyides 4 16 (7.60) 2 2 (3.80) 0 - P. heteromorpha 2 2 (0.95) 0 - 0 - P. lacustris 9 59 (28.10) 6 23 (44.25) 1 4 (36.40) P . ×alni 1 1 (0.48) 0 - 1 7 (63.60) P. niederhauserii 1 2 (0.95) 0 - 0 - P. pseudocryptogea 1 1 (0.48) 0 - 0 - P. honggalleglyana 1 6 (2.86) 0 - 0 - P. gallica 1 4 (1.90) 1 1 (1.90) 0 - Genus Phytophthora 12 210 (100) 9 52 (100) 2 11 (100) Pp. citrinum 5 19 (25.00) 0 - 0 - Pp. litorale 8 45 (59.21) 1 2 (66.67) 0 - Pp. montanum 1 1 (1.32) 0 - 0 - Pp. chamaehyphon 1 2 (2.63) 1 1 (33.33) 0 - Pp. paucipapillatum 2 3 (3.95) 0 - 0 - Pp. vexans 3 6 (7.89) 0 - 0 - Genus Phytopythium 8 76 (100) 1 3 (100) 0 - Py. aquatile 2 5 (83.33) 0 - 0 - Py. lutarium 1 1 (16.67) 0 - 0 - Genus Pythium 2 6 (100) 0 - 0 - G. heterothallicum 1 1 (33.33) 0 - 0 - G. intermedium 1 2 (66.67) 0 - 0 - Genus Globisporangium 1 3 (100) 0 - 0 - Total (all genera) 12 295 9 55 2 11 a Number of study sites, from which respective oomycete taxon has been isolated. b Number of the recovered isolates and their frequency of occurrence within a specific genus (%, shown in brackets). c -, non-applicable. Table 3 Observed and estimated diversity of identified (i.e., assigned to known species) oomycetes recovered from three substrate types (symptomatic bark, rhizosphere soil and water) in declining alder (Alnus glutinosa and A. incana) stands in Switzerland (13 sampling sites; for more information see Table 1). Observed species diversity Estimated species diversity a Sampling site Number of isolates Number of species Method b SC c Order Q d Diversity estimate of order q q D (lower CL) e q D (upper CL) f Eggenwil 41 10 R 0.81 0 7.53 6.03 9.03 1 4.12 2.86 5.38 2 2.63 1.73 3.54 Lauerz 78 9 R 0.92 0 5.26 4.24 6.29 1 3.72 3.00 4.44 2 3.00 2.36 3.63 Le Landeron 8 1 n.a. g n.a. n.a. n.a. n.a. n.a. Lignières 27 2 R 0.99 0 1.97 1.44 2.50 1 1.29 0.94 1.65 2 1.16 0.90 1.42 Magadino 20 8 E 0.91 0 8.19 6.25 10.12 1 7.49 5.70 9.28 2 7.10 5.11 9.08 Nussbaumen 20 4 E 1.00 0 4.00 3.01 4.99 1 3.43 2.76 4.11 2 3.21 2.52 3.89 Oberglatt 9 2 n.a. n.a. n.a. n.a. n.a. n.a. Orvin 49 7 R 0.91 0 5.30 3.99 6.61 1 3.94 3.11 4.77 2 3.37 2.73 4.01 Rottenschwil 56 7 R 0.93 0 5.42 4.42 6.42 1 3.87 2.94 4.79 2 3.11 2.23 3.98 Schwyzerbrugg 2 2 n.a. n.a. n.a. n.a. n.a. n.a. Steinerberg 5 2 n.a. n.a. n.a. n.a. n.a. n.a. Wil 35 4 R 0.97 0 3.63 3.01 4.25 1 2.72 2.20 3.23 2 2.27 1.72 2.82 Würenlos 11 4 E 1.00 0 4.22 1.40 7.04 1 3.62 1.75 5.49 2 2.94 1.08 4.80 a Calculated for a sample size of N=22 isolates. b R – rarefaction; E – extrapolation. c Estimated sample coverage. d Sensitivity of the index to rare or abundant species. e The bootstrap lower confidence limits for expected richness (value of 0.95). f The bootstrap upper confidence limits for expected richness (value of 0.95). g n.a. – not applicable. Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterials.docx Cite Share Download PDF Status: Published Journal Publication published 22 May, 2025 Read the published version in Microbial Ecology → Version 1 posted Editorial decision: Accepted 11 May, 2025 Reviews received at journal 11 May, 2025 Reviews received at journal 07 May, 2025 Reviews received at journal 29 Apr, 2025 Reviewers agreed at journal 17 Apr, 2025 Reviewers agreed at journal 16 Apr, 2025 Reviewers agreed at journal 15 Apr, 2025 Reviewers invited by journal 15 Apr, 2025 Submission checks completed at journal 15 Apr, 2025 First submitted to journal 14 Apr, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6029813","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":443370174,"identity":"b101e48d-2e05-4a9b-8a5b-38b21c5dc332","order_by":0,"name":"Mizeriene Goda","email":"","orcid":"","institution":"Swiss Federal Research Institute WSL","correspondingAuthor":false,"prefix":"","firstName":"Mizeriene","middleName":"","lastName":"Goda","suffix":""},{"id":443370175,"identity":"13728942-009c-4cdf-8762-4107a4420b9e","order_by":1,"name":"Vaidotas Lygis","email":"","orcid":"","institution":"State Scientific Research Institute Nature Research Centre","correspondingAuthor":false,"prefix":"","firstName":"Vaidotas","middleName":"","lastName":"Lygis","suffix":""},{"id":443370176,"identity":"37321723-66c4-41ab-82ab-bb52a2c50869","order_by":2,"name":"Prospero Simone","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYDACZjS+HFCogYGxgQQtxgwg9Xi1oIPEBkJa5Nu5Ex8XVDDkmbe3P3vwcY9N+obzBxsYfu7ArcXgMO9m4xlnGIplzpwxN5zxLC13w43EBsbeM3i0MPNuk+ZtY0icIZHDJs1z4HDuthuMDcyMbXgc1gzS8g+kJf2Z9J8Dh9PNgA7Dq4XhMEhLA0hLgpk0w4HDCWYHEvFrAfuF55hEsQQP0C89B9IM9wP9crAXn8P6z258zFNjkyfBDgyxHwds5CX7Dx988BOfwyBAIgFIsMG5BwhqAAJULaNgFIyCUTAKkAEAEt9Rw/HQTKYAAAAASUVORK5CYII=","orcid":"","institution":"Swiss Federal Research Institute WSL","correspondingAuthor":true,"prefix":"","firstName":"Prospero","middleName":"","lastName":"Simone","suffix":""}],"badges":[],"createdAt":"2025-02-14 10:38:37","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6029813/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6029813/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00248-025-02553-w","type":"published","date":"2025-05-22T15:58:08+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":80726268,"identity":"87d65ef2-a67f-4501-b77d-cd6c3b465382","added_by":"auto","created_at":"2025-04-16 11:49:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1184783,"visible":true,"origin":"","legend":"\u003cp\u003eTypologies of sampling sites and disease symptoms. (A) Riparian stand along a river; (B) Alder stand along a stream in a marsh; (C) Old bleeding lesions on a stem of grey alder (\u003cem\u003eAlnus incana\u003c/em\u003e); (D) Fresh bleeding lesion (tarry spot) on a stem of black alder (\u003cem\u003eAlnus glutinosa\u003c/em\u003e); (E) Grey alders showing crown dieback symptoms (sparse crowns, small leaves). (A: © Swiss Forest Protection, WSL; B-E: © Phytopathology, WSL)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6029813/v1/8e255266a7334dbbe9dabef5.png"},{"id":80726269,"identity":"eab7ef25-4cfa-4948-85df-73c73fce3fa5","added_by":"auto","created_at":"2025-04-16 11:49:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":323281,"visible":true,"origin":"","legend":"\u003cp\u003eOomycete sample completeness (sample coverage) based on the sampling design adopted in this study. The solid line represents sample coverage based on rarefaction, while the dashed line is based on extrapolation. The shading in grey indicates the 95% confidence intervals\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6029813/v1/0d9955b2b56d72d42e2b5117.png"},{"id":80727140,"identity":"088ebe79-5e6b-4bf2-adc3-7088159d0457","added_by":"auto","created_at":"2025-04-16 11:57:33","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":252865,"visible":true,"origin":"","legend":"\u003cp\u003eDiversity of identified (i.e., assigned to known species) oomycetes recovered in Switzerland from water samples, rhizosphere soil samples and bark lesions on symptomatic black alder (Alnus glutinosa) and grey alder (A. incana) trees. Numbers and letters in the parentheses after species names indicate the clade or group [7, 11, 13, 15] to which each species belongs. For full species names please see Table 2.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6029813/v1/3f9f3e5b8196d04818de200b.png"},{"id":80725477,"identity":"8d6aae2f-8620-4d3f-af9e-87acd78cc2e3","added_by":"auto","created_at":"2025-04-16 11:41:33","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":112734,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of Shannon diversity indices among oomycete communities recovered from the rhizosphere soil of symptomatic alder trees (A) and water samples (B) taken in declining alder stands at 12 (soil) and 9 (water) positive sites (for more information see Tables 1 and 3). Different letters above the bars indicate statistically significant differences at \u003cem\u003ep\u003c/em\u003e\u0026lt; 0.05 based on a Hutcheson's \u003cem\u003et\u003c/em\u003e-test. Error bars indicate values of confidence intervals.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6029813/v1/a14c059cb138ad0111815a34.png"},{"id":83460205,"identity":"d2c64bed-27c0-4582-af7d-96fee5a344a3","added_by":"auto","created_at":"2025-05-26 16:12:01","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2914281,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6029813/v1/bcc3812e-cd7c-4dc2-b812-1d8855d281d4.pdf"},{"id":80725474,"identity":"29aa6163-630f-4836-aa94-6df0957a2b21","added_by":"auto","created_at":"2025-04-16 11:41:32","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":151580,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterials.docx","url":"https://assets-eu.researchsquare.com/files/rs-6029813/v1/545d8c0743b22e9c511764f8.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Oomycete diversity and ecology in declining alder stands in Switzerland","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOomycetes are filamentous, fungus-like microbial eukaryotes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Thanks to their diverse lifestyles, pathogenicity and host range these microorganisms can be considered as one of the most successful groups of eukaryotes, which is globally distributed in almost all ecosystems on Earth [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although oomycetes are functionally heterogeneous [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], many of them are severe pathogens of agricultural crops and forest trees [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], with a significant impact on the global food security [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Regarding tree health, the genera \u003cem\u003ePhytophthora\u003c/em\u003e (\u003cem\u003eP.\u003c/em\u003e), \u003cem\u003ePythium\u003c/em\u003e (\u003cem\u003ePy.\u003c/em\u003e) and \u003cem\u003ePhytopythium\u003c/em\u003e (\u003cem\u003ePp.\u003c/em\u003e) are particularly relevant.\u003c/p\u003e \u003cp\u003eThe genus \u003cem\u003ePhytophthora\u003c/em\u003e includes more than 200 currently known species [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], many of them being plant pathogens [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and representing a phytosanitary threat to forest ecosystems worldwide [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. \u003cem\u003ePythium\u003c/em\u003e species are not only plant but also animal, algal or fungal pathogens, as well as saprophytes. Currently, this genus counts more than 140 species, occurring in a wide range of both aquatic and terrestrial habitats [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Over the years, the genus \u003cem\u003ePythium\u003c/em\u003e has been reclassified, and more recently, based on the phylogeny and the morphology of the sporangium, it has been subdivided into the four genera \u003cem\u003eOvatisporangium\u003c/em\u003e, \u003cem\u003eGlobisporangium\u003c/em\u003e, \u003cem\u003eElongisporangium\u003c/em\u003e and \u003cem\u003ePilasporangium\u003c/em\u003e [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The genus \u003cem\u003ePhytopythium\u003c/em\u003e is relatively new and was previously assigned to \u003cem\u003ePythium\u003c/em\u003e sp. clade K [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Uzuhashi \u003cem\u003eet al.\u003c/em\u003e [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] reclassified this genus as \u003cem\u003eOvatisporangium\u003c/em\u003e, and now \u003cem\u003eOvatisporangium\u003c/em\u003e and \u003cem\u003ePhytopythium\u003c/em\u003e are considered as synonyms [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This genus consists of 26 species [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] found in various habitats [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], mainly as necrotrophic generalists [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe introduction rate of pathogenic oomycetes into Europe\u0026rsquo;s natural ecosystems has increased dramatically over the last few decades [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and continues to rise. Since the early 1990\u0026rsquo;s, a severe decline of alder (\u003cem\u003eAlnus\u003c/em\u003e spp.) has been observed first in Britain and then across the entire continent [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The causal agent of this decline was found to be \u003cem\u003ePhytophthora alni sensu lato\u003c/em\u003e, a previously unknown \u003cem\u003ePhytophthora\u003c/em\u003e species [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Later, it was shown that \u003cem\u003eP. alni\u003c/em\u003e s. l. consists of three species, namely the hybrid \u003cem\u003eP.\u003c/em\u003e \u0026times;\u003cem\u003ealni\u003c/em\u003e, and its two parental species \u003cem\u003eP. \u0026times;multiformis\u003c/em\u003e, and \u003cem\u003eP. uniformis\u003c/em\u003e [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. These three species differ in morphology, genetic background, virulence, and geographic distribution [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn Switzerland, alder dieback has been observed since the early 2000s, and \u003cem\u003eP. alni\u003c/em\u003e s.l. was first officially isolated in 2008 from declining alders along the Reuss river [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In 2020, the isolates were re-analysed and definitively attributed to \u003cem\u003eP. \u0026times;alni\u003c/em\u003e [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. However, since then no comprehensive study has been carried out to investigate the diversity of \u003cem\u003ePhytophthora\u003c/em\u003e species in declining alder stands, although black (\u003cem\u003eAlnus glutinosa\u003c/em\u003e) and grey (\u003cem\u003eA. incana\u003c/em\u003e) alders are ecologically important species in riparian ecosystems such as river and stream banks, and lake shores. Recently, Schoebel \u003cem\u003eet al.\u003c/em\u003e [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] presented results of a study that investigated \u003cem\u003ePhytophthora\u003c/em\u003e community composition in Swiss watercourses over the period 2012\u0026ndash;2016. A total of 11 \u003cem\u003ePhytophthora\u003c/em\u003e species were detected, but no conclusions could be drawn linking the \u003cem\u003ePhytophthora\u003c/em\u003e species found to declining alders.\u003c/p\u003e \u003cp\u003eIn the present study, we aimed at answering the following two questions: i) what is the incidence and diversity of the oomycete species belonging to the genera \u003cem\u003ePhytophthora\u003c/em\u003e, \u003cem\u003ePythium\u003c/em\u003e, \u003cem\u003ePhytopythium\u003c/em\u003e (\u003cem\u003eOvatisporangium\u003c/em\u003e) and \u003cem\u003eGlobisporangium\u003c/em\u003e in declining alder stands in Switzerland, and ii) how do incidence and diversity of the isolated oomycetes vary across sampling sites and substrates (i.e., symptomatic bark, rhizosphere soil and water)?\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy sites\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eField sampling was conducted at 13 sites in Switzerland between April and September 2015 (Table 1). The sites were selected with the help of the local forest service at locations (196-840 m a.s.l.) where declining alders (\u003cem\u003eAlnus incana\u003c/em\u003e, \u003cem\u003eA. glutinosa\u003c/em\u003e) had been observed. They either consisted of mostly disturbed (management, cattle, hiking) stands along a watercourse (stream or river) or within a marshland (for examples see Fig. 1A and B). All sites were sampled only once, except for Rottenschwil and Orvin, which were sampled twice in different months (July and September) because of the presence of numerous declining trees. At each site, alder trees with symptoms of decline, such as bark lesions (bleeding cankers, tarry spots on the outer bark) along the stem or at the root collar, and crown thinning (Fig. 1C-E, [18]), were selected for sampling.\u003c/p\u003e\n\u003cp\u003eA total of 56 alder trees (42\u003cem\u003e\u0026nbsp;A. incana\u003c/em\u003e and 14 \u003cem\u003eA. glutinosa\u003c/em\u003e) were sampled (bark lesions and rhizosphere), ranging from one (Le Landeron and W\u0026uuml;renlos) to 11 (Orvin) trees per site (Table 1). In Schwyzerbrugg, no trees were sampled because it was too difficult to access them. Thirty-six of the sampled alder trees (64.3%) had bleeding bark lesions on the main stem or at the root collar (11 \u003cem\u003eA. glutinosa\u0026nbsp;\u003c/em\u003eand 25 \u003cem\u003eA. incana\u003c/em\u003e trees), 11 trees exhibited a thin crown with decline symptoms (one \u003cem\u003eA. glutinosa\u003c/em\u003e and ten \u003cem\u003eA. incana\u0026nbsp;\u003c/em\u003etrees), and nine trees showed both crown decline and bleeding bark lesions (two \u003cem\u003eA. glutinosa\u003c/em\u003e and seven \u003cem\u003eA. incana\u0026nbsp;\u003c/em\u003etrees). A total of 13 water samples were collected at 11 sites (two sites, Orvin and Rottenschwil, with two water samples).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOomycete sampling and isolation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter removing the bark at the margin of a stem lesion with a sterile knife, from one single lesion 20-30 pieces of phloem tissue were taken using a sterilized Jamshidi needle (2 mm in diameter) and placed on a selective CARP+ medium [24] directly in the field. The Petri plates were then incubated in the laboratory at 22 \u0026deg;C in the dark and for two to 14 days examined for the presence of oomycete-like hyphae growing out of the samples. When such hyphae were observed, an agar plug from the margin of the colony was transferred with a sterile toothpick onto a new Petri plate containing carrot piece agar (CPA) medium [25] and incubated at 22 \u0026deg;C in the dark to obtain a pure\u0026nbsp;culture.\u003c/p\u003e\n\u003cp\u003eSoil sampling was performed following the protocol of Tedersoo et al. [26]. Briefly, soil (in total about 1 kg per tree) was sampled along the four cardinal points around a symptomatic tree at 0.5-1.0 m distance from the root collar and at a depth of 5-20 cm using a spade. In the laboratory, soil was sieved through a sieve (mesh size 2 mm) and kept cool until further processing. If a waterbody (river, lake or pond) with banks covered with \u003cem\u003eA. glutinosa\u0026nbsp;\u003c/em\u003eor \u003cem\u003eA. incana\u0026nbsp;\u003c/em\u003etrees was present at the sampling site, approximately 1.5 l of water with sediments has also been collected from that waterbody.\u003c/p\u003e\n\u003cp\u003eThe presence of oomycetes in the collected soil and water samples was assessed using the baiting method proposed by Werres \u003cem\u003eet al\u003c/em\u003e. [27]. Briefly, three days after sampling at the latest, 200 ml of the sampled soil was put in a plastic container (15 cm x 15 cm x 4 cm) and covered with 400 ml of distilled water. Thereafter, four young, healthy rhododendron leaves were put on the water surface as baits. Similarly, 400 ml of water with sediments has been poured into a plastic container and baited with four young, healthy rhododendron leaves. The containers were then incubated for 16 h light period at 20 \u0026ordm;C and 8 h dark period at 15 \u0026ordm;C for maximum 10 days. For the isolation of oomycetes, five tissue samples (ca 3 mm x 3 mm in size) were cut from each symptomatic leaf (surface-sterilized) around the formed necrotic spots and placed on Petri plates with CPA medium. The plates were incubated at 22 \u0026deg;C in the dark and pure cultures were obtained as described above for phloem tissue samples [27]. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDNA extraction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo obtain pure mycelium for better DNA extraction, an agar plug removed from the margin of a growing pure culture was transferred to a new Petri plate containing liquid V8 medium [28]. The plates were then incubated for 5\u0026ndash;7 days at 22 \u0026deg;C in the dark until they were ca. 80 % covered by the culture. The mycelium was harvested on a filter paper by filtration with a B\u0026uuml;chner funnel and a vacuum pump. The collected mycelium was washed off the filter paper with sterile distilled water and placed in a freezer at -20 \u0026deg;C until the DNA extraction. After lyophilization, DNA was extracted using the DNeasy\u0026reg; Plant Mini kit or the DNeasy\u0026reg; 96 Plant Kit (Qiagen, 96 Hilden, Germany).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePCR and sequencing\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIsolates were identified to species by sequencing part of the ribosomal ITS region. PCR amplification was conducted in a 20-\u0026micro;l reaction volume containing final concentrations of 2x Master mix (JumpStart\u0026trade; RedTaq\u0026reg; Ready Mix (SigmaAldrich, Germany)), 0.625 \u0026micro;M of each ITS6 [29] and ITS4 [30] primers, and 1 \u0026micro;l template DNA. The target region was amplified by PCR using a Veriti\u0026trade; Thermal Cycler (Applied Biosystems, Foster City, CA, USA). Amplification was performed with initial denaturation at 95 \u0026deg;C for 2 min, following by 35 cycles of denaturation: 95 \u0026deg;C for 30 s, annealing: 55 \u0026deg;C for 30 s, extension: 72 \u0026deg;C for 2 min, final extension: 72 \u0026deg;C for 10 min. The PCR products were purified using Illustra\u0026trade; ExoProStar\u0026trade; PCR and Sequence Reaction Clean-Up Kit (Sigma-Aldrich, Germany), according to the manufacturer\u0026rsquo;s instructions. For sequencing, BigDye\u0026trade; Terminator v. 3.1 Cycle Sequencing Kit and BigDye\u0026trade; x-Terminator Purification Kit (Applied Biosystems, Carlsbad, CA) were used according to manufacturer\u0026rsquo;s protocol. The sequencing was performed on an ABI 3130 or ABI 3730xl capillary sequencer (Applied Biosystems, USA). The obtained sequences were assembled and edited using the software CLC Main Workbench version 8.0 Beta 4 (Qiagen, Bioinformatics, Denmark). For species identification, sequences (~800 bp) were compared with publicly available sequences in the National Center for Biotechnology Information (NCBI; https://blast.ncbi.nlm.nih.gov/Blast.cgi) database with Blast algorithm. Two sequences were considered to belong to the same species if they showed at least 99 % similarity. Representative sequences of all identified species are available in the NCBI database (https://www.ncbi.nlm.nih.gov/) under the accession numbers PV082471 to PV082524 (for details see Table S1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssessment of oomycete diversity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIndividual-based rarefaction of Hill numbers (D) [31] was used to estimate oomycete diversity across various sites and substrates. The diversity indicators are characterized by the order \u003cem\u003eq\u003c/em\u003e, which determines the sensitivity of the index to rare or abundant species. The diversity order \u003cem\u003eq\u003c/em\u003e=0 (\u003csup\u003e0\u003c/sup\u003eD) represents species richness and shows the diversity of all species. The diversity order of \u003cem\u003eq\u003c/em\u003e=1 (\u003csup\u003e1\u003c/sup\u003eD) displays \u0026ldquo;typical\u0026rdquo; species and functions as Shannon Diversity. Finally, the diversity order of \u003cem\u003eq\u003c/em\u003e=2 (\u003csup\u003e2\u003c/sup\u003eD) represents Simpson diversity and shows the diversity of dominant species [32]. Interpolated/extrapolated curves were produced with the iNEXT package (v.3.0.0) [33] in RStudio v. 4.2.3 (RStudio PBC, Boston, USA). To investigate whether uneven sample sizes from different sites affect total oomycete species diversity, we produced interpolated/extrapolated curves using iNEXT based on sample coverage (hereinafter SC) data. The iNEXT package \u003cem\u003eestimateD\u003c/em\u003e function was used to calculate the diversity estimates for the minimum sample size between sites, by excluding uninformative sites. To determine whether diversity differences between sites were statistically significant, the 95% confidence intervals were compared. Since visually comparing all confidence intervals was difficult, the significance of the differences in species diversity in water and soil among sites was also determined by calculating and comparing Shannon diversity indices between sites using Hutcheson\u0026apos;s \u003cem\u003et\u003c/em\u003e-test [34].\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eOomycete incidence\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 400 oomycete (\u003cem\u003ePhytophthora\u003c/em\u003e, \u003cem\u003ePythium,\u003c/em\u003e \u003cem\u003ePhytopythium\u0026nbsp;\u003c/em\u003eand\u003cem\u003e\u0026nbsp;Globisporangium\u003c/em\u003e) isolates were recovered from the three different substrates (bark, soil, water). The overall isolation rate was 47.2%, with oomycetes recovered at all 13 sites. The highest incidence of oomycetes was obtained from soil samples (330 isolates, 82.5% isolation rate), followed by water samples (59 isolates, 14.7% isolation rate), and bark samples (11 isolates, 2.7% isolation rate). Out of the 400 oomycete isolates, 361 (90.3%) could be successfully assigned to a known species, for a total of 23 identified species (Table 2). The remaining 39 isolates could not be unequivocally assigned to a specific oomycete species and were thus removed from further analyses. Among all genera, \u003cem\u003ePhytophthora\u003c/em\u003e was the most abundant with 273 isolates (75.6%), followed by \u003cem\u003ePhytopythium\u003c/em\u003e (79 isolates), \u003cem\u003ePythium\u003c/em\u003e (six isolates) and \u003cem\u003eGlobisporangium\u003c/em\u003e (three isolates) (Table 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOomycete diversity across sampling sites\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe highest oomycete diversity was observed in Eggenwil (ten species), Lauerz (nine species), Magadino (eight species), and Orvin and Rottenschwil (seven species each) (Table 3). On the other hand, the sites Le Landeron, Schwyzerbrugg, Steinerberg, Ligni\u0026egrave;res and Oberglatt exhibited the lowest oomycete diversity with only one to two species isolated from each site (Table 3). Based on the incidence data generated from sampling units (i.e., same sample size across sites), the coverage-based rarefaction and extrapolation sampling curve indicates that the sampling effort in this study was sufficient to catch up to 85% of the expected oomycete diversity (Fig. 2). As stated above, Eggenwil had the highest observed species diversity, but based on rarefied and extrapolated estimates for 22 isolates, Magadino had the highest species richness (\u003csup\u003e0\u003c/sup\u003eD \u0026ndash; 8.19), as well as the highest estimations for the most common (together with Eggenwil: \u003csup\u003e1\u003c/sup\u003eD \u0026ndash; 7.49 and 7.53, respectively) and most abundant (\u003csup\u003e2\u003c/sup\u003eD \u0026ndash; 7.10) species (Table 3). Seven of the 13 sites sampled had SC scores greater than 0.90, which allows a reliable estimation of oomycete diversity (Table 3).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePhytophthora\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e. Phytophthora\u0026nbsp;\u003c/em\u003eisolates were recovered at all 13 sites and belonged to 13 different species spanning seven different ITS clades (Fig. 3; [7]).\u0026nbsp;On average, three \u003cem\u003ePhytophthora\u003c/em\u003e species were detected in each site. The highest diversity was observed at Magadino with a total of six species, most of which belonged to the ITS clade 6 (Fig. 3). Twelve out of 13 detected \u003cem\u003ePhytophthora\u0026nbsp;\u003c/em\u003especies (all except \u003cem\u003eP. citrophthora\u003c/em\u003e) were recovered from soil samples, five from water (including \u003cem\u003eP. citrophthora\u003c/em\u003e), and two from bark lesions (\u003cem\u003eP.\u0026nbsp;\u003c/em\u003e\u0026times;\u003cem\u003ealni\u003c/em\u003e and \u003cem\u003eP. lacustris\u003c/em\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePhytopythium\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e.\u0026nbsp;\u003c/em\u003eThe genus \u003cem\u003ePhytopythium\u0026nbsp;\u003c/em\u003ewas found at nine of the 13 sites and included seven known species (Table 2, Fig. 3). Rottenschwil showed the highest \u003cem\u003ePhytopythium\u003c/em\u003e species diversity, with a total of four different species detected. All six detected \u003cem\u003ePhytopythium\u0026nbsp;\u003c/em\u003especies were recovered from soil samples, two from water, and none from bark lesions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePythium\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eand\u003cstrong\u003e\u003cem\u003e\u0026nbsp;Globisporangium\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e.\u0026nbsp;\u003c/em\u003eRepresentatives of genera \u003cem\u003ePythium\u0026nbsp;\u003c/em\u003eand \u003cem\u003eGlobisporangium\u0026nbsp;\u003c/em\u003ewere rarely detected at the sampled sites and were isolated exclusively from soil samples (Fig. 3). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOomycete diversity across different substrate types\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOomycete species diversity and incidence showed a significant variation within and among substrates (Fig. 3). Only one species \u0026ndash; \u003cem\u003eP. lacustris\u003c/em\u003e \u0026ndash; was present and abundant in all substrates, while 16 species were restricted to a specific substrate, mainly soil.\u003c/p\u003e\n\u003cp\u003eThe rhizosphere of symptomatic alder trees harboured the most diverse oomycete community, with a total of 22 known species (Table 2, Fig. 3). However, most of these species were rather rare and each was represented by less than 10 isolates. Typical species present in the rhizosphere of declining alder trees were \u003cem\u003eP. plurivora\u003c/em\u003e, \u003cem\u003eP. lacustris\u003c/em\u003e, \u003cem\u003ePp. litorale\u003c/em\u003e and \u003cem\u003ePp. citrinum\u0026nbsp;\u003c/em\u003e(altogether they included 80.0% of the identified oomycete isolates recovered from soil). Based on 95% confidence intervals, significant differences were observed among some sites in oomycete diversity in the soil (Fig. S1). These differences were confirmed by a Hutcheson\u0026apos;s \u003cem\u003et\u003c/em\u003e-test comparing Shannon diversity indices (Fig. 4A).\u003c/p\u003e\n\u003cp\u003eThe aquatic oomycete community included a total of seven known species (five \u003cem\u003ePhytophthora\u003c/em\u003e and two \u003cem\u003ePhytopythium\u003c/em\u003e species) (Table 2, Fig. 3). The most common species in the water samples were \u003cem\u003eP. lacustris\u003c/em\u003e and\u003cem\u003e\u0026nbsp;P. plurivora\u0026nbsp;\u003c/em\u003e(23 isolates each; altogether they comprised 83.6% of the identified oomycete isolates recovered from water). Although the overall incidence of both species was the same, the first was found at 6 sites whereas the latter only at four sites. Notably, \u003cem\u003eP. citrophthora\u003c/em\u003e was found only in water samples. Four \u003cem\u003ePhytophthora\u003c/em\u003e species (\u003cem\u003eP. lacustris\u003c/em\u003e, \u003cem\u003eP. gallica\u003c/em\u003e, \u003cem\u003eP. gonapodyides\u003c/em\u003e and \u003cem\u003eP. plurivora\u003c/em\u003e) and two \u003cem\u003ePhytopythium\u003c/em\u003e species (\u003cem\u003ePp. chamaehyphon\u0026nbsp;\u003c/em\u003eand \u003cem\u003ePp. litorale\u003c/em\u003e) were identified in both soil and water samples. The differences among sites in oomycete species diversity in water were not as marked as in the soil (Fig. S2, Fig. 4B), but the number of water samples analysed was considerably lower than that of soil samples.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFinally, only two \u003cem\u003ePhytophthora\u0026nbsp;\u003c/em\u003especies were isolated from alder bark lesions, namely, \u003cem\u003eP. \u0026times;alni\u003c/em\u003e, the causal agent of alder decline, and \u003cem\u003eP. lacustris\u003c/em\u003e (Fig. 3).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e\u003cstrong\u003eOomycete abundance and diversity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOomycetes were found at all 13 sites sampled, with \u003cem\u003ePhytophthora\u003c/em\u003e being the most abundant genus followed by \u003cem\u003ePhytopythium\u003c/em\u003e. The other two investigated genera, \u003cem\u003ePythium\u003c/em\u003e and \u003cem\u003eGlobisporangium\u003c/em\u003e, were clearly less frequent. Among the three substrates analysed, soil yielded the highest number of isolates and species, highlighting once again its importance as a reservoir for these microorganisms (e.g., [35-37]). Previous surveys of terrestrial and aquatic oomycete communities occasionally showed higher species diversity in water bodies compared to tree rhizosphere or forest soils (e.g., [35]).\u0026nbsp;According to Catal\u0026agrave; et al. [35], water bodies, and rivers in particular, seem to concentrate the inoculum of oomycetes of large areas, especially after rainy periods when the inoculum is discharged into larger bodies of water as runoff. On the other hand, the success of oomycete recovery from one or another substrate may depend on other factors, including the detection technique applied (e.g., [38]).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe found a higher oomycete species diversity, in particular of \u003cem\u003ePhytophthora\u0026nbsp;\u003c/em\u003especies, in the rhizosphere of declining alder stands compared to other studies carried out in Austria [39], Italy [40], Poland [41] and Turkey [42]. Bregant et al. [43] isolated a similar number (12) of\u0026nbsp;\u003cem\u003ePhytophthora\u003c/em\u003e species from the rhizosphere of declining \u003cem\u003eA. glutinosa\u003c/em\u003e trees in Portugal, but only five of them were common to our study.\u0026nbsp;Riit et al. [44]\u0026nbsp;used a metagenomic approach for detection of oomycetes\u0026nbsp;in the rhizosphere soil of\u0026nbsp;declining alder trees across the Fennoscandian and Baltic countries and detected DNA of ten\u003cem\u003e\u0026nbsp;Phytophthora\u003c/em\u003e species\u0026nbsp;and 28 \u003cem\u003ePythium\u003c/em\u003e species. These differences could be partially due to detection methods applied, but also to the influence of abiotic and biotic factors like sampling season, geographic location, and vegetation type (e.g., [45,\u0026nbsp;46]).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe overall diversity of \u003cem\u003ePhytophthora\u003c/em\u003e species in our water samples was similar to that reported in surveys conducted in other European countries (e.g. [39, 47, 48]), and in Australia [49]. Of the other oomycete genera, only two species of \u003cem\u003ePhytopythium\u003c/em\u003e were isolated at low frequencies from water samples during the present study. This is quite surprising as most taxa of the families \u003cem\u003ePythiaceae\u003c/em\u003e and \u003cem\u003ePeronosporaceae\u003c/em\u003e are dependent on aquatic environments and are usually abundantly recovered from natural water bodies (e.g., [48, 50, 51]). This low success of oomycete recovering from water samples may be explained (inter alia) by the fact that we used an \u003cem\u003eex-situ\u003c/em\u003e baiting method, while an \u003cem\u003ein-situ\u003c/em\u003e baiting would probably have allowed capturing more species [38].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBark lesions on \u003cem\u003eAlnus\u003c/em\u003e species yielded the lowest number and diversity of oomycetes - we were able to isolate only two \u003cem\u003ePhytophthora\u003c/em\u003e species. A lower incidence and diversity of \u003cem\u003ePhytophthora\u003c/em\u003e species in the alder bark than in the soil was also reported in other studies (e.g., [52]) and may be due to several factors, including a suboptimal isolation method (in our case, direct plating of bark samples in the field) or occasional sampling of old lesions in which \u003cem\u003ePhytophthora\u003c/em\u003e might not be active anymore. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInsights into the ecology of the isolated oomycete species\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eThe genus\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003ePhytophthora\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePhytophthora plurivora,\u003c/em\u003e \u003cem\u003eP. lacustris\u003c/em\u003e and \u003cem\u003eP. gonapodyides\u003c/em\u003e were the most abundant species in the rhizosphere soil and water samples, all of which are widespread in natural and agricultural ecosystems.\u003cem\u003e\u0026nbsp;Phytophthora plurivora\u003c/em\u003e is an aggressive soil-borne plant pathogen with a broad host range and worldwide distribution, often associated with declining forest trees (e.g., [53]). The high incidence of \u003cem\u003eP. plurivora\u0026nbsp;\u003c/em\u003ein declining alder stands in Switzerland is in agreement with the results of previous studies conducted in Europe (e.g., [41-43, 54, 55]).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlthough the clade 6 member \u003cem\u003eP. lacustris\u003c/em\u003e is usually regarded as a saprotroph or opportunistic plant pathogen, which is common in riparian ecosystems in Europe and North America [56-58], there is a growing concern about its involvement in the aetiology of tree diseases. O\u0026rsquo;Hanlon et al. [59] speculated that this species may be responsible for black alder decline in Northern Ireland. The pathogen was also found infecting this alder species\u003cem\u003e\u0026nbsp;\u003c/em\u003ein Portugal [60], as well as causing diseases in several other plant hosts in Europe [57]. In our study, \u003cem\u003eP. lacustris\u003c/em\u003e, together with\u0026nbsp;\u003cem\u003eP. \u0026times;alni\u003c/em\u003e were the only oomycete species isolated from alder bark lesions. Given the predominance of \u003cem\u003eP. lacustris\u003c/em\u003e in Swiss watercourses [23], its exact role in causing alder decline in Switzerland should be further investigated.\u003c/p\u003e\n\u003cp\u003eThe third most frequently isolated\u003cem\u003e\u0026nbsp;Phytophthora\u0026nbsp;\u003c/em\u003especies in our study, \u003cem\u003eP. gonapodyides\u003c/em\u003e, also belongs to ITS clade 6 and\u003cem\u003e\u0026nbsp;\u003c/em\u003ehas been traditionally regarded as a weak parasite with saprophytic abilities, usually present in aquatic environments [61]. In Europe, this species was already associated with declining broadleaved trees [53]. However, although in North America \u003cem\u003eP. gonapodyides\u003c/em\u003e is considered an important species involved in the etiology of native alder species dieback [56], its role in alder decline in Europe is still unclear.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll the other ten \u003cem\u003ePhytophthora\u003c/em\u003e species identified in our study were restricted to one or two sites and mostly present only in soil. Among them, seven species were already known to occur in Switzerland [23], whereas for \u003cem\u003eP. heteromorpha\u003c/em\u003e, \u003cem\u003eP. niederhauserii\u003c/em\u003e, and \u003cem\u003eP. pseudocryptogea\u003c/em\u003e this is the first report for the country. \u003cem\u003ePhytophthora heteromorpha\u003c/em\u003e was first described in Italy from riparian habitats and in inoculation experiments proved to be pathogenic on \u003cem\u003eA. incana\u003c/em\u003e [62]. \u003cem\u003ePhytophthora niederhauserii\u003c/em\u003e is\u003cem\u003e\u0026nbsp;\u003c/em\u003ea highly pathogenic polyphagous species associated with ornamentals, fruit trees and native plants, distributed worldwide, including Europe [63, 64]. Finally, \u003cem\u003eP. pseudocryptogea\u003c/em\u003e is a species within the \u003cem\u003eP. cryptogea\u003c/em\u003e species complex that was officially described in 2015 [65]. In Turkey, \u003cem\u003eP. pseudocryptogea\u003c/em\u003e was recovered from the rhizosphere of declining oaks [66], whereas in Canada the species was reported to cause root rot on western white pine (\u003cem\u003ePinus monticola\u003c/em\u003e) in seed orchards [67]. In Italy, it was isolated from declining alder trees [68], which indicates its potential to be pathogenic on trees.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eThe genera\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Phytopythium, Pythium and Globisporangium\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe rhizosphere soil of declining alders was found to host a diverse assemblage of species of the genera \u003cem\u003ePhytopythium\u003c/em\u003e, \u003cem\u003ePythium\u003c/em\u003e, and \u003cem\u003eGlobisporangium\u003c/em\u003e, which, to our knowledge, had never been previously investigated in natural ecosystems in Switzerland. These genera are known to include numerous plant pathogens mainly of tree seedlings and herbaceous plants [11, 69]. In this study, two \u003cem\u003ePhytopythium\u0026nbsp;\u003c/em\u003especies, namely \u003cem\u003ePp. litorale\u0026nbsp;\u003c/em\u003eand \u003cem\u003ePp. citrinum\u003c/em\u003e, were quite commonly isolated from rhizosphere soil of declining alders\u003cem\u003e.\u003c/em\u003e Derviş et al. [70] speculated that \u003cem\u003ePp. litorale\u0026nbsp;\u003c/em\u003emay be the causal agent of the severe decline of oriental plane in Turkey, while Polat et al. [71] associated it to a kiwifruit dieback. In several European countries, USA, and Vietnam, \u003cem\u003ePp. litorale\u003c/em\u003e was found in watercourses [39, 51, 59]. \u003cem\u003ePhytopythium citrinum\u003c/em\u003e is known as a common inhabitant of aquatic and riparian ecosystems in Europe and North America [47, 51]. Also, it was isolated from the rhizosphere of declining black alder and pedunculate oak trees in Poland [55, 72]. In a recent study by Christova [47], both \u003cem\u003ePp. citrinum\u003c/em\u003e and \u003cem\u003ePp. litorale\u003c/em\u003e showed moderate to high potential to infect several woody plant species, as well as some perennial and herbaceous plants. For this reason, both organisms were determined as pathogens with a wide host range. The other five \u003cem\u003ePhytopythium\u003c/em\u003e species detected in this study were less frequent and limited to a few sites. While \u003cem\u003ePp. vexans\u003c/em\u003e is widespread worldwide and shows pathogenicity towards economically important woody hosts to which it causes root rot, damping off, crown rot, stem rot, or patch canker (e.g., [64], and references therein), the published information on the ecology of\u003cem\u003e\u0026nbsp;Pp. montanum\u003c/em\u003e,\u0026nbsp;\u003cem\u003ePp. chamaehyphon\u003c/em\u003e, and\u0026nbsp;\u003cem\u003ePp. paucipapillatum\u003c/em\u003e, is rather scarce and does not refer to \u003cem\u003eAlnus\u003c/em\u003e species. Similarly, neither of the two \u003cem\u003ePythium\u003c/em\u003e species\u0026nbsp;found in the present study\u0026nbsp;\u0026ndash;\u0026nbsp;\u003cem\u003ePy. aquatile\u003c/em\u003e and\u0026nbsp;\u003cem\u003ePy. lutarium\u003c/em\u003e, and neither\u0026nbsp;of the two \u003cem\u003eGlobisporangium\u003c/em\u003e species \u0026ndash;\u0026nbsp;\u003cem\u003eG. heterothallicum\u0026nbsp;\u003c/em\u003eand\u003cem\u003e\u0026nbsp;G. intermedium\u003c/em\u003e, were associated with alder previously.\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eConfirming previous studies in Europe and North America, our analyses revealed a diverse and abundant community of oomycetes in declining alder stands in Switzerland, in particular in the rhizosphere of symptomatic trees. The species recovered ranged from known saprotrophs or opportunistic plant pathogens to aggressive pathogens. Noteworthy, only two \u003cem\u003ePhytophthora\u003c/em\u003e species were isolated from bark lesions on alders, namely, \u003cem\u003eP. \u0026times;alni\u003c/em\u003e, the known causal agent of alder decline, and \u003cem\u003eP. lacustris\u003c/em\u003e. Although this might be partially explained by the fact that not all sampled bark lesions were still active, it could also suggest that the observed alder decline might be due to pathogens acting only in the root system and/or abiotic stress factors. Future studies are needed to build up understanding of the ecological role of all oomycete species recovered in such ecosystems as well as their possible interactions with alder and a changing environment. Understanding how oomycete communities are assembled in stands (e.g. based on functional traits, [\u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e73\u003c/span\u003e]) with different health status would also help to further clarify their role in forest ecosystems.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eSupplementary Information\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe online version contains supplementary material available at ........... (the link may be added later, after acceptance).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank Tetyana Tsykun for her help in the field and Quirin Kupper and Esther Jung for their help in the laboratory.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSP and GM designed the study and conducted the field sampling. GM analysed the data and wrote the first draft of the manuscript. SP, GM and VL edited, reviewed, and approved the final version.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by a Sciex-NMSch Fellowship (Project Code 14.035) for GM. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRepresentative sequences of all identified species are available in the NCBI database (https://www.ncbi.nlm.nih.gov/) under the accession numbers PV082471 to PV082524.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo approval was required.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLamour KH, Win J, Kamoun S (2007) Oomycete genomics: new insights and future directions. FEMS Microbiol Lett 274:1\u0026ndash;8. https://doi.org/10.1111/j.1574-6968.2007.00786.x\u003c/li\u003e\n\u003cli\u003eThines M (2014) Phylogeny and evolution of plant pathogenic oomycetes - a global overview. Eur J Plant Pathol 138:431\u0026ndash;447. https://doi.org/10.1007/s10658-013-0366-5\u003c/li\u003e\n\u003cli\u003eFiore-Donno AM, Bonkowski M (2021) Different community compositions between obligate and facultative oomycete plant parasites in a landscape-scale metabarcoding survey. Biol Fertil Soils 57:245\u0026ndash;256. https://doi.org/10.1007/s00374-020-01519-z\u003c/li\u003e\n\u003cli\u003eDerevnina L, Petre B, Kellner R, Dagdas YF, Sarowar MN, Giannakopoulou A et al (2016) Emerging oomycete threats to plants and animals.\u003cem\u003e \u003c/em\u003ePhilos Trans R Soc Lond B Biol Sci 371:20150459. https://doi.org/10.1098/rstb.2015.0459\u003c/li\u003e\n\u003cli\u003eFawke S, Doumane M, Schornack S (2015) Oomycete Interactions with Plants: Infection Strategies and Resistance Principles. Microbiol Mol Biol Rev 79:263\u0026ndash;280. https://doi.org/10.1128/MMBR.00010-15\u003c/li\u003e\n\u003cli\u003eFones HN, Bebber DP, Chaloner TM, Kay WT, Steinberg G, Gurr SJ (2020) Threats to global food security from emerging fungal and oomycete crop pathogens. Nat Food 1:332\u0026ndash;342. https://doi.org/10.1038/s43016-020-0075-0\u003c/li\u003e\n\u003cli\u003eAbad ZG, Burgess TI, Bourret T, Bensch K, Cacciola S, Scanu B, et al (2023). \u003cem\u003ePhytophthora\u003c/em\u003e: taxonomic and phylogenetic revision of the genus. Stud Mycol 106:259\u0026ndash;348. https://doi.org/10.3114/sim.2023.106.05 \u003c/li\u003e\n\u003cli\u003eBoevink PC, Birch PRJ, Turnbull D, Whisson SC (2020) Devastating intimacy: the cell biology of plant\u0026ndash;\u003cem\u003ePhytophthora\u003c/em\u003e interactions. New Phytol 228:445\u0026ndash;458. https://doi.org/10.1111/nph.16650\u003c/li\u003e\n\u003cli\u003eKeri\u0026ouml; S, Daniels HA, G\u0026oacute;mez-Gallego M, Tabima JF, Lenz RR, S\u0026oslash;ndreli KL et al (2020) From genomes to forest management \u0026ndash; tackling invasive \u003cem\u003ePhytophthora\u003c/em\u003e species in the era of genomics. Can J Plant Pathol 42:1\u0026ndash;29. https://doi.org/10.1080/07060661.2019.1626910\u003c/li\u003e\n\u003cli\u003eKageyama K (2014) Molecular taxonomy and its application to ecological studies of \u003cem\u003ePythium\u003c/em\u003e species. J Gen Plant Pathol 80:314\u0026ndash;326. https://doi.org/10.1007/s10327-014-0526-2\u003c/li\u003e\n\u003cli\u003eUzuhashi S, Tojo M, Kakishima M (2010) Phylogeny of the genus \u003cem\u003ePythium\u003c/em\u003e and description of new genera. Mycoscience 51:337\u0026ndash;365. https://doi.org/10.1007/s10267-010-0046-7\u003c/li\u003e\n\u003cli\u003eBaten MdA, Asano T, Motohashi K, Ishiguro Y, Rahman MZ, Inaba S et al (2014) Phylogenetic relationships among \u003cem\u003ePhytopythium\u003c/em\u003e species, and re-evaluation of \u003cem\u003ePhytopythium fagopyri \u003c/em\u003ecomb. nov., recovered from damped-off buckwheat seedlings in Japan. Mycol Prog 13:1003. https://doi.org/10.1007/s11557-014-1003-1\u003c/li\u003e\n\u003cli\u003ede Cock AWAM, Lodhi AM, Rintoul TL, Bala K, Robideau GP, Abad ZG et al (2015) \u003cem\u003ePhytopythium\u003c/em\u003e: molecular phylogeny and systematics. Persoonia 34(1):25\u0026ndash;39. https://doi.org/10.3767/003158515X685382\u003c/li\u003e\n\u003cli\u003eLodhi AM, Shahzad S, Syed RN (2020) The Genus \u003cem\u003ePhytopythium\u003c/em\u003e. In: Rai M, Abd-Elsalam KA, Ingle AP (eds)\u003cem\u003e Pythium: \u003c/em\u003eDiagnosis, Diseases and Management,\u003cem\u003e \u003c/em\u003e1st edn. CRC Press, Boca Raton, pp 45-76. https://doi.org/10.1201/9780429296406\u003c/li\u003e\n\u003cli\u003eBaten MdA, Mingzhu L, Motohashi K, Ishiguro Y, Rahman MZ, Suga H, Kageyama K (2015) Two new species, \u003cem\u003ePhytopythium iriomotense\u003c/em\u003e sp. nov. and \u003cem\u003eP. aichiense\u003c/em\u003e sp. nov., isolated from river water and water purification sludge in Japan. Mycol Prog 14:2. https://doi.org/10.1007/s11557-015-1027-1\u003c/li\u003e\n\u003cli\u003eSantini A, Ghelardini L, De Pace C, Desprez-Loustau ML, Capretti P, Chandelier A et al (2013) Biogeographical patterns and determinants of invasion by forest pathogens in Europe. New Phytol 197:238\u0026ndash;250. https://doi.org/10.1111/j.1469-8137.2012.04364.x\u003c/li\u003e\n\u003cli\u003eBrasier CM, Rose J, Gibbs JN (1995) An unusual \u003cem\u003ePhytophthora\u003c/em\u003e associated with widespread alder mortality in Britain. Plant Pathol 44:999\u0026ndash;1007. https://doi.org/10.1111/j.1365-3059.1995.tb02658.x\u003c/li\u003e\n\u003cli\u003eStreito JC (2003) Phytophthora disease of alder: identification and distribution. In: Gibbs JN, Van Dijk C, Webber JF (eds) Phytophthora disease of alder in Europe. Edinburgh, UK: Forestry Commission Bulletin No. 126:25\u0026ndash;38\u003c/li\u003e\n\u003cli\u003eHusson C, Aguayo J, Revellin C, Frey P, Ioos R, Mar\u0026ccedil;ais B (2015) Evidence for homoploid speciation in \u003cem\u003ePhytophthora alni\u003c/em\u003e supports taxonomic reclassification in this species complex. Fungal Genet Biol 77:12\u0026ndash;21. https://doi.org/10.1016/j.fgb.2015.02.013\u003c/li\u003e\n\u003cli\u003eMar\u0026ccedil;ais B (2018) \u003cem\u003ePhytophthora alni\u003c/em\u003e species complex (alder \u003cem\u003ePhytophthora\u003c/em\u003e). Wallingford, UK: CABI Compendium 40948. https://doi.org/10.1079/cabicompendium.40948\u003c/li\u003e\n\u003cli\u003eMeier F, Engesser R, Forster B, Odermatt O, Angst A (2009) Forstschutz-\u0026Uuml;berblick 2008 [Forest protection overview 2008]. Birmensdorf: Eidgen\u0026ouml;ssische Forschungsanstalt WSL, 24 p (In German).\u003c/li\u003e\n\u003cli\u003eMizeriene G, Cerny K, Zyka V, Bakonyi J, Nagy ZA, Oliva J, Redondo MA, Corcobado T, Prospero S (2020) Patterns of genetic diversification in the invasive hybrid plant pathogen \u003cem\u003ePhytophthora\u0026times; alni \u003c/em\u003eand its parental species \u003cem\u003eP. uniformis\u003c/em\u003e. Phytopathology 110:1959\u0026ndash;1969. https://doi.org/10.1094/PHYTO-12-19-0475-R\u003c/li\u003e\n\u003cli\u003eSchoebel CN, Prospero S, Rigling D, Ruffner B (2024) Fishing for \u003cem\u003ePhytophthora\u003c/em\u003e in watercourses of the highly urbanized Swiss Plateau. Mycol Prog 23:17. https://doi.org/10.1007/s11557-024-01951-7\u003c/li\u003e\n\u003cli\u003eErwin DC, Ribeiro OK (1996) Phytophthora\u003cem\u003e \u003c/em\u003ediseases worldwide. APS Press, St. Paul, MN. https://doi.org/10.1046/j.1365-3059.1998.0179a.x\u003c/li\u003e\n\u003cli\u003eWerres S, Marwitz R, Man In\u0026apos;t veld WA, De CockWAM, Bonants, PJM et al (2001) \u003cem\u003ePhytophthora ramorum \u003c/em\u003esp. nov., a new pathogen on \u003cem\u003eRhododendron \u003c/em\u003eand \u003cem\u003eViburnum.\u003c/em\u003e Mycol Res 105:1155\u0026ndash;1165. https://doi.org/10.1017/S0953756201004865\u003c/li\u003e\n\u003cli\u003eTedersoo L, Bahram M, Polme S, Koljalg U, Yorou S, Wardle DA, Lindahl BD (2014) Disentangling global soil fungal diversity. Science 346:1052\u0026ndash;1053. https://doi.org/10.1126/science.aaa1185\u003c/li\u003e\n\u003cli\u003eWerres S, Hahn R, Themann K (1997) Application of different techniques to detect \u003cem\u003ePhytophthora\u003c/em\u003e spp. in roots of commercially produced \u003cem\u003eChamaecyparis lawsoniana. \u003c/em\u003eZ Pflanzenkr Pflanzenschutz 104:474\u0026ndash;482.\u003c/li\u003e\n\u003cli\u003eMiller PM (1955) V-8 juice agar as a general purpose medium for fungi and bacteria. Phytopathology 45:461\u0026ndash;462.\u003c/li\u003e\n\u003cli\u003eCooke DEL, Drenth A, Duncan JM, Wagels G, Brasier CM (2000) A molecular phylogeny of \u003cem\u003ePhytophthora\u003c/em\u003e and related oomycetes. Fungal Genet Biol 30:17\u0026ndash;32. https://doi.org/10.1006/fgbi.2000.1202 \u003c/li\u003e\n\u003cli\u003eWhite TJ, Bruns T, Lee S, Taylor J (1990) Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, et al. (eds) PCR Protocols: A Guide to Methods and Applications. Academic Press, Inc., San Diego, USA; London, England, UK, pp 315\u0026ndash;322.\u003c/li\u003e\n\u003cli\u003eJost L (2006) Entropy and diversity. Oikos 113:363\u0026ndash;375. https://doi.org/10.1111/j.2006.0030-1299.14714.x\u003c/li\u003e\n\u003cli\u003eChao A, Gotelli NJ, Hsieh TC, Sander EL, Ma KH, Colwell RK, Ellison AM (2014) Rarefaction and extrapolation with Hill numbers: a framework for sampling and estimation in species diversity studies. Ecol Monogr 84:45\u0026ndash;67. https://doi.org/10.1890/13-0133.1\u003c/li\u003e\n\u003cli\u003eHsieh TC, Ma KH, Chao A (2016) iNEXT: an R package for rarefaction and extrapolation of species diversity (Hill numbers). Methods Ecol Evol 7:1451\u0026ndash;1456. https://doi.org/10.1111/2041-210X.12613\u003c/li\u003e\n\u003cli\u003eHutcheson K (1970) A Test for comparing diversities based on the Shannon formula. J Theor Biol 29: 151\u0026ndash;154. https://doi.org/10.1016/0022-5193(70)90124-4\u003c/li\u003e\n\u003cli\u003eCatal\u0026agrave; S, P\u0026eacute;rez-Sierra A, Abad-Campos P (2015) The use of genus-specific amplicon pyrosequencing to assess \u003cem\u003ePhytophthora\u003c/em\u003e species diversity using eDNA from soil and water in Northern Spain. PLoS ONE 10:e0119311.\u003cu\u003e doi:10.1371/journal.pone.0119311\u003c/u\u003e\u003c/li\u003e\n\u003cli\u003eJung T, La Spada F, Pane A, Aloi F, Evoli M, Horta Jung M et al (2019) Diversity and Distribution of \u003cem\u003ePhytophthora\u003c/em\u003e Species in Protected Natural Areas in Sicily. Forests 10:259. https://doi.org/10.3390/f10030259\u003c/li\u003e\n\u003cli\u003eJung T, Scanu B, Brasier CM, Webber J, Milenković I, Corcobado T et al (2020) A survey in natural forest ecosystems of Vietnam reveals high diversity of both new and described \u003cem\u003ePhytophthora\u003c/em\u003e taxa including \u003cem\u003eP. ramorum\u003c/em\u003e. Forests 11:93. https://doi.org/10.3390/f11010093\u003c/li\u003e\n\u003cli\u003ePettitt TR (2023) Monitoring oomycetes in water: combinations of methodologies used to answer key monitoring questions. Front Hortic\u003cem\u003e \u003c/em\u003e2:1210535. https://doi.org/10.3389/fhort.2023.1210535\u003c/li\u003e\n\u003cli\u003eCorcobado T, Cech TL, Daxer A, Ďatkov\u0026aacute; H, Janou\u0026scaron;ek J, Patra S et al (2023) \u003cem\u003ePhytophthora\u003c/em\u003e, \u003cem\u003eNothophytophthora\u003c/em\u003e and \u003cem\u003eHalophytophthora\u003c/em\u003e diversity in rivers, streams and riparian alder ecosystems of Central Europe. Mycol Prog 22:50. https://doi.org/10.1007/s11557-023-01898-1\u003c/li\u003e\n\u003cli\u003eBregant C, Sanna GP, Bottos A, Maddau L, Montecchio L, Linaldeddu BT (2020) Diversity and Pathogenicity of \u003cem\u003ePhytophthora\u003c/em\u003e Species Associated with Declining Alder Trees in Italy and Description of \u003cem\u003ePhytophthora alpina\u003c/em\u003e sp. nov. Forests 11:848. https://doi.org/10.3390/f11080848\u003c/li\u003e\n\u003cli\u003eTrzewik A, Orlikowski LB, Oszako T, Nowakowska J, Orlikowska T (2015) The characterization of \u003cem\u003ePhytophthora \u003c/em\u003eisolates obtained from diseased \u003cem\u003eAlnus glutinosa\u003c/em\u003e in Poland. Balt For 21:44\u0026ndash;50.\u003c/li\u003e\n\u003cli\u003eAday Kaya AG, Lehtij\u0026auml;rvi A, Şaşmaz Y, Nowakowska JA, Oszako T, Doğmuş Lehtij\u0026auml;rvi HT, Woodward S (2018). \u003cem\u003ePhytophthora\u003c/em\u003e species detected in the rhizosphere of \u003cem\u003eAlnus glutinosa \u003c/em\u003estands in the floodplain forests of Western Turkey. For Pathol 48:e12470. https://doi.org/10.1111/efp.12470\u003c/li\u003e\n\u003cli\u003eBregant C, Batista E, Hil\u0026aacute;rio S, Linaldeddu BT, Alves A (2023) \u003cem\u003ePhytophthora\u003c/em\u003e Species Involved in \u003cem\u003eAlnus glutinosa \u003c/em\u003eDecline in Portugal. Pathogens 12:276. https://doi.org/10.3390/pathogens12020276\u003c/li\u003e\n\u003cli\u003eRiit T, Cleary M, Adamson K, Blomquist M, Burokienė D, Marčiulynienė D et al (2023) Oomycete Soil Diversity Associated with \u003cem\u003eBetula\u003c/em\u003e and \u003cem\u003eAlnus\u003c/em\u003e in Forests and Urban Settings in the Nordic\u0026ndash;Baltic Region. J Fungi 9:926. https://doi.org/10.3390/jof9090926\u003c/li\u003e\n\u003cli\u003eSarker SR, Burgess TI, Hardy GESJ, McComb J (2023a) Closing the gap between the number of \u003cem\u003ePhytophthora\u003c/em\u003e species isolated through baiting a soil sample and the number revealed through metabarcoding. Mycol Prog 23:39. https://doi.org/10.1007/s11557-023-01892-7\u003cu\u003e \u003c/u\u003e\u003c/li\u003e\n\u003cli\u003eSarker SR, McComb J, Hardy GESJ, Burgess TI (2023b) Sample volume affects the number of \u003cem\u003ePhytophthora\u003c/em\u003e and \u003cem\u003ePhytopythium \u003c/em\u003especies detected by soil baiting. European J Plant Pathol 166:303\u0026ndash;313. https://doi.org/10.1007/s10658-023-02661-8\u003c/li\u003e\n\u003cli\u003eChristova PK (2024) Fishing for estuarine oomycetes. Diversity 16:530. https://doi.org/10.3390/d16090530\u003c/li\u003e\n\u003cli\u003eMatsiakh I, Oszako T, Kramarets V, Nowakowska JA (2016) \u003cem\u003ePhytophthora\u003c/em\u003e and \u003cem\u003ePythium\u003c/em\u003e species detected in rivers of the Polish-Ukrainian border areas. Balt For 22:230\u0026ndash;238.\u003c/li\u003e\n\u003cli\u003eH\u0026uuml;berli D, Hardy GESJ, White D, Williams N, Burgess TI (2013) Fishing for \u003cem\u003ePhytophthora\u003c/em\u003e from Western Australia\u0026rsquo;s waterways: a distribution and diversity survey. Australas Plant Pathol 42:251\u0026ndash;260. https://doi.org/10.1007/s13313-012-0195-6\u003c/li\u003e\n\u003cli\u003eEl-Hissy FT (1994) \u003cem\u003eOomycetes\u003c/em\u003e and \u003cem\u003eChytridiomycetes\u003c/em\u003e (\u003cem\u003eMastigomycotina\u003c/em\u003e) from water bodies in T\u0026uuml;bingen region (Germany). J Basic Microbiol 34:67\u0026ndash;76. https://doi.org/10.1002/jobm.3620340202\u003c/li\u003e\n\u003cli\u003eShrestha SK, Zhou Y, Lamour K (2013) Oomycetes baited from streams in Tennessee 2010\u0026ndash;2012. Mycologia 105:1516\u0026ndash;1523.\u003cu\u003e https://doi.org/10.3852/13-010\u003c/u\u003e\u003c/li\u003e\n\u003cli\u003eJung T, Blaschke M (2004) \u003cem\u003ePhytophthora\u003c/em\u003e root and collar rot of alders in Bavaria: Distribution, modes of spread and possible management strategies. Plant Pathol 53:197\u0026ndash;208. https://doi.org/10.1111/j.0032-0862.2004.00957.x\u003c/li\u003e\n\u003cli\u003eJung T, P\u0026eacute;rez-Sierra A, Dur\u0026aacute;n A, Horta Jung M, Balci Y, Scanu B (2018) Canker and decline diseases caused by soil- and airborne \u003cem\u003ePhytophthora\u003c/em\u003e species in forests and woodlands. Persoonia 40:182\u0026ndash;220. https://doi.org/10.3767/persoonia.2018.40.08\u003c/li\u003e\n\u003cli\u003eČern\u0026yacute; K, Tom\u0026scaron;ovsk\u0026yacute; M, Mr\u0026aacute;zkov\u0026aacute; M, Strnadov\u0026aacute; V (2011) The present state of knowledge on \u003cem\u003ePhytophthora\u003c/em\u003e spp. diversity in forest and ornamental woody plants in the Czech Republic. N Z J For Sci 41S:S75\u0026ndash;S82.\u003c/li\u003e\n\u003cli\u003eTkaczyk M, Szmidla H, Sikora K (2023) Occurrence of \u003cem\u003ePhytophthora\u003c/em\u003e species in the rhizosphere of dying black alder \u003cem\u003eAlnus glutinosa\u003c/em\u003e in central and northeastern Poland. Sylwan 167:452\u0026minus;460. https://doi.org/10.26202/sylwan.2023040 \u003c/li\u003e\n\u003cli\u003eSims LL, Sutton W, Reeser P, Hansen EM (2015) The \u003cem\u003ePhytophthora\u003c/em\u003e species assemblage and diversity in riparian alder ecosystems of western Oregon, USA. Mycologia 107:889\u0026ndash;902. https://doi.org/10.3852/14-255\u003c/li\u003e\n\u003cli\u003eNechwatal J, Bakonyi J, Cacciola SO, Cooke DEL, Jung T, Nagy Z\u0026Aacute; et al (2013) The morphology, behaviour and molecular phylogeny of \u003cem\u003ePhytophthora\u003c/em\u003e taxon Salixsoil and its redesignation as \u003cem\u003ePhytophthora lacustris\u003c/em\u003e sp. nov. Plant Pathol 62:355\u0026ndash;369. https://doi.org/10.1111/j.1365-3059.2012.02638.x\u003c/li\u003e\n\u003cli\u003eBourret TB, Mehl HK, Aram K, Rizzo DM (2023) Rhododendron leaf baiting of coastal California watersheds for \u003cem\u003ePhytophthora\u003c/em\u003e and \u003cem\u003eNothophytophthora\u003c/em\u003e. Mycol Prog 22:62. https://doi.org/10.1007/s11557-023-01910-8\u003c/li\u003e\n\u003cli\u003eO\u0026apos;Hanlon R, Wilson J, Cox D (2020) Investigations into \u003cem\u003ePhytophthora\u003c/em\u003e dieback of alder along the river Lagan in Belfast, Northern Ireland. Irish Forestry 77:33\u0026ndash;48. \u003c/li\u003e\n\u003cli\u003eKanoun-Boul\u0026eacute; M, Vasconcelos T, Gaspar J, Vieira S, Dias-Ferreira C, Husson C (2016) \u003cem\u003ePhytophthora \u0026times;alni \u003c/em\u003eand \u003cem\u003ePhytophthora lacustris\u003c/em\u003e associated with common alder decline in Central Portugal. For Pathol 46:174\u0026ndash;176. https://doi.org/10.1111/efp.12273\u003c/li\u003e\n\u003cli\u003eBrasier CM, Cooke DE, Duncan JM, Hansen EM (2003) Multiple new phenotypic taxa from trees and riparian ecosystems in \u003cem\u003ePhytophthora gonapodyides\u0026ndash;P. megasperma\u003c/em\u003e ITS Clade 6, which tend to be high-temperature tolerant and either inbreeding or sterile. Mycol Res 107:277\u0026ndash;290. https://doi.org/10.1017/S095375620300738X\u003c/li\u003e\n\u003cli\u003eBregant C, Rossetto G, Sasso N, Montecchio L, Maddau L, Linaldeddu BT (2024) Diversity and distribution of \u003cem\u003ePhytophthora\u003c/em\u003e species across different types of riparian vegetation in Italy with the description of \u003cem\u003ePhytophthora heteromorpha\u003c/em\u003e sp. nov. Int J Syst Evol Microbiol 74:006272. https://doi.org/10.1099/ijsem.0.006272\u003c/li\u003e\n\u003cli\u003eAbad ZG, Abad JA, Cacciola SO, Pane A, Faedda R, Moralejo E et al (2014) \u003cem\u003ePhytophthora niederhauserii \u003c/em\u003esp. nov., a polyphagous species associated with ornamentals, fruit trees and native plants in 13 countries. Mycologia 106:431\u0026ndash;447. https://doi.org/10.3852/12-119\u003c/li\u003e\n\u003cli\u003eBeluz\u0026aacute;n F, Miarnau X, Torguet L, Armengol J, Abad-Campos P (2022) Survey of oomycetes associated with root and crown rot of almond in Spain and pathogenicity of \u003cem\u003ePhytophthora niederhauserii\u003c/em\u003e and \u003cem\u003ePhytopythium vexans\u003c/em\u003e to \u0026lsquo;Garnem\u0026rsquo; rootstock. Agriculture 12:294. https://doi.org/10.3390/agriculture12020294\u003c/li\u003e\n\u003cli\u003eSafaiefarahani B, Mostowfizadeh-Ghalamfarsa R, Hardy GEStJ, Burgess TI (2015) Re-evaluation of the \u003cem\u003ePhytophthora cryptogea\u003c/em\u003e species complex and the description of a new species, \u003cem\u003ePhytophthora pseudocryptogea\u003c/em\u003e sp. nov. Mycol Progress 14:108 https://doi.org/10.1007/s11557-015-1129-9\u003c/li\u003e\n\u003cli\u003eKurbetli I, Woodward S, Aydoğdu M, S\u0026uuml;l\u0026uuml; G, \u0026Ouml;zben S (2022) \u003cem\u003ePhytophthora plurivora\u003c/em\u003e and \u003cem\u003ePhytophthora pseudocryptogea\u003c/em\u003e isolated from soils supporting declining oaks (\u003cem\u003eQuercus robur\u003c/em\u003e L.) in İstanbul, Turkey. For Path 52:e12782. https://doi.org/10.1111/efp.12782\u003c/li\u003e\n\u003cli\u003eShamoun SF, Feau N, Islam A, Ruff K, Drugmand B (2024) Survey of oomycetes and pathogenicity of \u003cem\u003ePhytophthora cinnamomi\u003c/em\u003e associated with root rot disease of western white pine (\u003cem\u003ePinus monticola\u003c/em\u003e). Can J Plant Pathol 46:648\u0026ndash;660. https://doi.org/10.1080/07060661.2024.2383588\u003c/li\u003e\n\u003cli\u003eSeddaiu S, Linaldeddu BT (2020) First Report of \u003cem\u003ePhytophthora acerina\u003c/em\u003e, \u003cem\u003eP. plurivora\u003c/em\u003e, and \u003cem\u003eP. pseudocryptogea \u003c/em\u003eAssociated with Declining Common Alder Trees in Italy. Plant Dis 104:1874 https://doi.org/10.1094/PDIS-01-20-0186-PDN\u003c/li\u003e\n\u003cli\u003eHendrix FF, Campbell WA (1973) Pythiums as Plant Pathogens. Annu Rev Phytopathol 11:77\u0026ndash;98. https://doi.org/10.1146/annurev.py.11.090173.000453\u003c/li\u003e\n\u003cli\u003eDerviş S, T\u0026uuml;rk\u0026ouml;lmez Ş, \u0026Ccedil;ift\u0026ccedil;i O, \u0026Ouml;zer G, Ulubaş Ser\u0026ccedil;e \u0026Ccedil;, Dikilitas M (2020) \u003cem\u003ePhytopythium litorale\u003c/em\u003e: A Novel Killer Pathogen of Plane (\u003cem\u003ePlatanus orientalis\u003c/em\u003e) Causing Canker Stain and Root and Collar Rot. Plant Dis 104:2642\u0026ndash;2648. https://doi.org/10.1094/PDIS-01-20-0141-RE\u003c/li\u003e\n\u003cli\u003ePolat Z, Kaymak S, G\u0026uuml;ltekin MA, Bayraktar H, \u0026Ouml;zer G (2023) First report of \u003cem\u003ePhytopythium litorale\u003c/em\u003e associated with dieback disease of kiwifruit in Turkey. J Plant Pathol 105:1761\u0026ndash;1762. https://doi.org/10.1007/s42161-023-01510-1\u003c/li\u003e\n\u003cli\u003eTkaczyk M (2020) \u003cem\u003ePhytopythium\u003c/em\u003e: origin, differences and meaning in modern plant pathology. Folia For Pol Ser A For 62:227\u0026ndash;232. https://doi.org/10.2478/ffp-2020-0022\u003c/li\u003e\n\u003cli\u003eRedondo MA, Boberg J, Stenlid J, Oliva J (2018) Contrasting distribution patterns between aquatic and terrestrial \u003cem\u003ePhytophthora\u003c/em\u003e species along a climatic gradient are linked to functional traits. ISME J 12:2967\u0026ndash;2980. https://doi.org/10.1038/s41396-018-0229-3\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1\u003c/strong\u003e Information about the 13 sites sampled in this study and the number of samples collected.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"891\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eSite\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003eCoordinates (WGS84)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eWaterbody name (type)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eSampled\u003cem\u003e\u0026nbsp;Alnus\u0026nbsp;\u003c/em\u003especies\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eForest type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003eSamples (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eLongitude\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eLatitude\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eBark\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eSoil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eWater\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eEggenwil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.3384\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.36432\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eReuss (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eLauerz\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.58025\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.03799\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eChlausenbach (stream)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e, \u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003eLe Landeron\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e7.05001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e47.0499\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eVieille Thielle (duct)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eLigni\u0026egrave;res\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e7.07807\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.09019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eUnnamed (pond)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003eMagadino\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e8.8694\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e46.15581\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eTicino (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eMarsh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eNussbaumen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.82237\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.61628\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eNussbommersee (lake)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eMarsh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003eOberglatt\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e8.51323\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e47.48062\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eGlatt (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eMarsh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eOrvin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e7.20246\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.15602\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eL\u0026rsquo;Orvine (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e, \u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003eRottenschwil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e8.373\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e47.32264\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eReuss (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e, \u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eSchwyzerbrugg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.7123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.15264\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eBiber (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eSteinerberg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.57789\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.04523\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eGoldbach (stream)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eWil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.51377\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.61742\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eSchwarzbach (stream)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e, \u003cem\u003eA. incana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eW\u0026uuml;renlos\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e8.37022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e47.43536\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eLimmat (river)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e\u003cem\u003eA. glutinosa\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003eRiparian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e Incidence of identified (i.e., assigned to known species) oomycete taxa recovered from three substrate types (soil, water and bark) sampled in declining alder (Alnus glutinosa and A. incana) stands in Switzerland (for more information see Materials and Methods section).\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eTaxa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 133px;\"\u003e\n \u003cp\u003eSoil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003eWater\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 135px;\"\u003e\n \u003cp\u003eBark\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003eSites\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003eIsolates\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eSites\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eIsolates\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eSites\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003eIsolates\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. citrophthora\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e-\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e3 (5.80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. plurivora\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e113 (53.80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e23 (44.20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. pseudosyringae\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e1 (0.48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. bilorbang\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e3 (1.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. chlamydospora\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e2 (0.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. gonapodyides\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e16 (7.60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e2 (3.80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. heteromorpha\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e2 (0.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. lacustris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e59 (28.10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e23 (44.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e4 (36.40)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e.\u003cem\u003e\u0026nbsp;\u0026times;alni\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e1 (0.48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e7 (63.60)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. niederhauserii\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e2 (0.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. pseudocryptogea\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e1 (0.48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. honggalleglyana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e6 (2.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eP. gallica\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e4 (1.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e1 (1.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003eGenus\u003cem\u003e\u0026nbsp;Phytophthora\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e210 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e52 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e11 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePp. citrinum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e19 (25.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePp. litorale\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e45 (59.21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e2 (66.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePp. montanum\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e1 (1.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePp. chamaehyphon\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e2 (2.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e1 (33.33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePp. paucipapillatum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e3 (3.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePp. vexans\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e6 (7.89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003eGenus\u003cem\u003e\u0026nbsp;Phytopythium\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e76 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e3 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePy. aquatile\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e5 (83.33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003ePy. lutarium\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e1 (16.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003eGenus \u003cem\u003ePythium\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e6 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eG. heterothallicum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e1 (33.33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 159px;\"\u003e\n \u003cp\u003e\u003cem\u003eG. intermedium\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e2 (66.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eGenus \u003cem\u003eGlobisporangium\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e3 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 159px;\"\u003e\n \u003cp\u003eTotal (all genera)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e295\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003eNumber of study sites, from which respective oomycete taxon has been isolated.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eb\u003c/sup\u003eNumber of the recovered isolates and their frequency of occurrence within a specific genus (%, shown in brackets).\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ec\u003c/sup\u003e-, non-applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e Observed and estimated diversity of identified (i.e., assigned to known species) oomycetes recovered from three substrate types (symptomatic bark, rhizosphere soil and water) in declining alder (Alnus glutinosa and A. incana) stands in Switzerland (13 sampling sites; for more information see Table 1).\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"101%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 37px;\"\u003e\n \u003cp\u003eObserved species diversity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"6\" valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003eEstimated species diversity\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003eSampling site\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 7px;\"\u003e\n \u003cp\u003eNumber of isolates\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10px;\"\u003e\n \u003cp\u003eNumber of species\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003eMethod\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 6px;\"\u003e\n \u003cp\u003eSC\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003eOrder\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eQ\u003c/em\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12px;\"\u003e\n \u003cp\u003eDiversity\u003cbr\u003e\u0026nbsp;estimate of\u003cbr\u003eorder \u003cem\u003eq\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e\u003cem\u003eq\u003c/em\u003eD (lower CL)\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12px;\"\u003e\n \u003cp\u003e\u003cem\u003eq\u003c/em\u003eD (upper CL)\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eEggenwil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e7.53\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e6.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e9.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e5.38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e2.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eLauerz\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e5.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e4.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e6.29\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.44\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.63\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003eLe Landeron\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 7px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003en.a.\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eLigni\u0026egrave;res\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e1.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e2.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e1.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e1.65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e1.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eMagadino\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e8.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e6.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e10.12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e7.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e5.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e9.28\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e7.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e5.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e9.08\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eNussbaumen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e3.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.11\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 18px;\"\u003e\n \u003cp\u003eOberglatt\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 7px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eOrvin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e5.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e3.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e6.61\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e3.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.77\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eRottenschwil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e5.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e4.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e6.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.79\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.98\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 18px;\"\u003e\n \u003cp\u003eSchwyzerbrugg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 7px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 18px;\"\u003e\n \u003cp\u003eSteinerberg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 7px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003en.a.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eWil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e3.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e2.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.23\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e2.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e2.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003eW\u0026uuml;renlos\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 7px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 10px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 8px;\"\u003e\n \u003cp\u003eE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 6px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e7.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e5.49\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e2.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003eCalculated for a sample size of N=22 isolates.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eb\u003c/sup\u003eR \u0026ndash; rarefaction; E \u0026ndash; extrapolation.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ec\u003c/sup\u003eEstimated sample coverage.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ed\u003c/sup\u003eSensitivity of the index to rare or abundant species.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ee\u003c/sup\u003eThe bootstrap lower confidence limits for expected richness (value of 0.95).\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ef\u003c/sup\u003eThe bootstrap upper confidence limits for expected richness (value of 0.95).\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eg\u003c/sup\u003en.a. \u0026ndash; not applicable.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"microbial-ecology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"meco","sideBox":"Learn more about [Microbial Ecology](https://www.springer.com/journal/248)","snPcode":"248","submissionUrl":"https://submission.nature.com/new-submission/248/3","title":"Microbial Ecology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Alnus, bark lesions, rhizosphere soil, water, isolation","lastPublishedDoi":"10.21203/rs.3.rs-6029813/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6029813/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study we assessed the occurrence and diversity of four oomycete genera (\u003cem\u003ePhytophthora\u003c/em\u003e, \u003cem\u003ePhytopythium\u003c/em\u003e, \u003cem\u003ePythium\u003c/em\u003e and \u003cem\u003eGlobisporangium\u003c/em\u003e) in 13 declining alder (\u003cem\u003eAlnus glutinosa\u003c/em\u003e and \u003cem\u003eA. incana\u003c/em\u003e) stands in Switzerland. For this, we sampled and analysed soil from tree rhizosphere, water from streams and rivers along which the stands were located, and symptomatic alder bark. The overall isolation rate was 47.2%, with a total of 400 oomycete isolates recovered at all 13 sites. The highest incidence of oomycete isolates was in soil samples (baiting, 82.5% isolation rate), followed by water (baiting, 14.7%), and bark (direct isolation, 2.7%). Of all recovered oomycete isolates, 90.3% could be successfully assigned to a known species, for a total of 23 species identified, including both preferential saprotrophs and pathogens. Among all genera, \u003cem\u003ePhytophthora\u003c/em\u003e was the most abundant with 273 isolates (75.6%), followed by \u003cem\u003ePhytopythium\u003c/em\u003e, \u003cem\u003ePythium\u003c/em\u003e and \u003cem\u003eGlobisporangium\u003c/em\u003e. Oomycete species diversity showed a significant variation among substrates. Only one species \u0026ndash; \u003cem\u003ePhytophthora lacustris\u003c/em\u003e \u0026ndash; was abundant in all substrates, while 16 species were restricted to a specific substrate, mainly soil. The rhizosphere of symptomatic alder trees harboured the most diverse oomycete community, highlighting once again the importance of soil as a reservoir for these microorganisms. Only two \u003cem\u003ePhytophthora\u003c/em\u003e species were isolated from alder bark lesions, namely, \u003cem\u003eP. \u0026times;alni\u003c/em\u003e, the known causal agent of alder decline, and \u003cem\u003eP. lacustris\u003c/em\u003e. The low recovery rate of \u003cem\u003eP. \u0026times;alni\u003c/em\u003e might be due to attempts to isolate it from old, inactive lesions, but may also suggest that alder decline might be caused by other oomycetes infecting the root system of the trees.\u003c/p\u003e","manuscriptTitle":"Oomycete diversity and ecology in declining alder stands in Switzerland","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-16 11:41:28","doi":"10.21203/rs.3.rs-6029813/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Accepted","date":"2025-05-11T14:09:19+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-11T11:55:38+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-07T23:59:19+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-29T11:58:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"236645962768380641776764687532507585977","date":"2025-04-17T08:20:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"254376261941463046218105984594804071514","date":"2025-04-16T15:21:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"258763058602338577197139239662041526708","date":"2025-04-15T15:07:13+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-15T14:58:32+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-04-15T05:48:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Microbial Ecology","date":"2025-04-14T17:27:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"microbial-ecology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"meco","sideBox":"Learn more about [Microbial Ecology](https://www.springer.com/journal/248)","snPcode":"248","submissionUrl":"https://submission.nature.com/new-submission/248/3","title":"Microbial Ecology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"97203fb1-d515-4408-97cd-d386f9461822","owner":[],"postedDate":"April 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-05-26T16:07:10+00:00","versionOfRecord":{"articleIdentity":"rs-6029813","link":"https://doi.org/10.1007/s00248-025-02553-w","journal":{"identity":"microbial-ecology","isVorOnly":false,"title":"Microbial Ecology"},"publishedOn":"2025-05-22 15:58:08","publishedOnDateReadable":"May 22nd, 2025"},"versionCreatedAt":"2025-04-16 11:41:28","video":"","vorDoi":"10.1007/s00248-025-02553-w","vorDoiUrl":"https://doi.org/10.1007/s00248-025-02553-w","workflowStages":[]},"version":"v1","identity":"rs-6029813","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6029813","identity":"rs-6029813","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}