Fusarium species pathogenic to Urochloa brizantha in the north de Minas Gerais, Brazil

Fusarium species pathogenic to Urochloa brizantha in the north de Minas Gerais, Brazil | 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 Fusarium species pathogenic to Urochloa brizantha in the north de Minas Gerais, Brazil Fernanda Letycia Amaral, Maria de Fátima Gonçalves Fernandes, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7188016/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract In Brazil, the sudden death disease of Marandu grass ( Urochloa brizantha cv. Marandu) has caused grassland degradation. In the north of Minas Gerais state, a disease has been reported in pastures with similar symptoms to the sudden death of grasses. Thus, the objectives of this study were (i.) to identify Fusarium species associated with the sudden death disease of Marandu grass using molecular phylogeny and morphological markers and (ii.) to test the pathogenicity of Fusarium isolates on Marandu and Xaraés cultivars. All isolates used in this work were obtained from typical cultures of the genus Fusarium , grown from isolated tissues of Marandu grass with symptoms of the disease, collected in the North region of Minas Gerais, Brazil. Twelve phylogenetic species were identified among the 17 isolates based on comparing partial sequences of the elongation factor 1-α gene (TEF-1-α). These species belong to the F. fujikuroi (FFSC, n = 10) and F. oxysporum (FOSC, n = 5) species complexes. In the pathogenicity test, the isolates induced symptoms of leaf yellowing, shoot drying, and stem rot in the cultivars Marandu and Xaraés, especially the isolates belonging to the FFSC. The Fusarium sp. 4 strain will be described and elevated to the species level, representing a new phylogenetic species in the FFSC. Our study has shown that several species of Fusarium cause pathogenicity to Marandu and Xaraés grasses, which can serve as an inoculum source for crops of great agricultural significance. However, this pathosystem can also harbor new species of Fusarium . In our work, we demonstrated for the first time the pathogenicity of Fusarium species in the cultivars Marandu and Xaraés. Fusarium fujikuroi species complex fusariosis marandu grass molecular phylogeny sudden death syndrome Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Introduction The genus Urochloa (sin. Brachiaria ) originated in Africa and propagates through seeds, being extensively cultivated as a forage plant due to its adaptability to average fertility soils. Being native to the African continent, it possesses high potential for adaptability to the Brazilian tropical climate and soils from the Cerrado (Nunes et al. 1984 ; Lorenzi 2008 ). The area occupied by the pasture was 164.57 million hectares in 2023, representing 19.35% of land used for livestock (MapBioma 2023). U. brizantha cv. Marandu was implemented in Brazil in 1984, being cultivated mainly in the North and Central West regions. However, since the 1990s, reports of the sudden death disease causing the degradation of grassland areas in Brazil have arisen. The disease was associated with abiotic variables (environmental factors) and primarily with biotic factors such as Pythium perillum , Fusarium sp. and Rhizoctonia solani (Zúñiga et al. 1998 ; Duarte et al. 2007 ), which causes collar rot in this forage plant. In the northern region of the state of Minas Gerais, Brazil, there were also reports of grasslands death exhibiting similar symptoms as in the previously mentioned regions. Fusarium species may modify the plant physiology by producing various mycotoxins which are detrimental to their hosts (Leslie and Summerell 2006 ). Their main characteristic is the production of elongated, fusiform, septate conidia (Gerlach and Nirenberg 1982 ). Fusarium species may behave as pathogens, saprophytes or endophytes, depending on the host and the environmental conditions (Bentley et al. 2007 ; Summerell et al. 2011 ). One of the earliest studies associating Fusarium species with native grasses and cultivated plants occurred in Australia (Burgess 1988; Burgess and Summerell 1992 ). This genus was obtained from samples of vegetal residues and soils, as well as from host plants within natural pathosystems (Burgess and Summerell 1992 ; Laurence et al. 2015 ). Species of the fujikuroi complex are amongst the most common diseases in crops of economic prominence. In Asia, various species from this complex were described, such as F . verticillioides , F . sacchari , F . proliferatum and F. fujikuroi , causing diseases in rice, sugar-cane and corn (Hsuan et al. 2011 ). Although F. sacchari is considered an endophytic fungus in Oryza australiensis , better known as wild rice in Australia, it is the main causal agent of the pokkah boeng disease in sugarcane (Petrovic et al. 2013 ). In addition, F. madaense , F. andyazi and Fusarium mirum were associated with grasses of agricultural importance in Africa and Brazil (Costa et al. 2022 ). As well as F. circinatum causing canker in Pinus sp., which is disseminated in many countries, including Brazil, and is an important disease problem in forestry (Wingfield et al. 2008 ; Steenkamp et al. 2012 ; Pfenning et al. 2014 ). Many fungi species were described as endophytic in forages from the genus Urochloa in Kenya, the genus Fusarium being the most abundant in the radicular system of these plants (Kago et al. 2016 ). A study based on phylogenetic analysis in Brazil revealed two new species: F . caapi and F . brachiariae , belonging to the African clade of the species complex Fusarium fujikuroi (FFSC), sharing the main morphological characteristics with F . mundagurra and F . nygamai . These two new species were isolated from U. brizantha and U. decumbens asymptomatic seeds (Costa et al. 2021 ). However, many species from the F. fujikuroi complex have a preference for grasses, surviving as endophytes or causing diseases (Leslie and Summerell 2006 ; Costa et al. 2021 ). Therefore, native and cultivated grasses may host a great diversity of pathogenic species. Additionally, these pathosystems may also host news Fusarium species. Hence, we aimed to identify Fusarium species associated with marandu grass in municipalities from the North of Minas Gerais state, Brazil, and to test the pathogenicity of these isolates to U. brizantha cv. Marandu and Xaraés. Materials and Methods Isolates of Fusarium sp. The isolates used in the present study were obtained from monosporic cultures from typical cultures of the genus Fusarium , obtained from disinfected tissues (70% ethanol and 1% sodium hypochlorite) of U. brizantha cv. Marandu. In order to obtain the isolates, small fragments of plant tissues exhibiting symptoms of leaf yellowing and drought of the aerial portion (sudden death) were used. Samples were collected in the field in the municipality of Buritizeiro, located in the northern region of Minas Gerais, Brazil, to obtain fungal isolates (Table 1 ). Table 1 Isolates of Fusarium sp. obtained from marandu grass plants (Urochloa brizantha cv. Marandu) in the municipality of Buritizeiro, MG, Brazil. Species Code Geographic Origin Host F . proliferatum CML3880 Buritizeiro-MG U. brizantha F . caapi CML 3881 Buritizeiro-MG U. brizantha F . oxysporum CML 3882 Buritizeiro-MG U. brizantha F . caapi CML 3883 Buritizeiro-MG U. brizantha F . oxysporum CML 3885 Buritizeiro-MG U. brizantha F . verticillioides CML 3886 Buritizeiro-MG U. brizantha F. verticillioides CML 3887 Buritizeiro-MG U. brizantha F . oxysporum CML 3888 Buritizeiro-MG U. brizantha Fusarium sp.4 CML 3889 Buritizeiro-MG U. brizantha F . oxysporum CML 3890 Buritizeiro-MG U. brizantha Fusarium sp.4 CML 3892 Buritizeiro-MG U. brizantha F . oxysporum CML 3896 Buritizeiro-MG U. brizantha Fusarium sp. LPF-FBM15 Buritizeiro-MG U. brizantha F . verticillioides LPF-FBM16 Buritizeiro-MG U. brizantha Fusarium sp. LPF-FBM17 Buritizeiro-MG U. brizantha CML – Mycological Collection of Lavras, Departament of Phytopathology, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil. LPF – Laboratory of Phytopathology Research, Universidade de Minas Gerais (ICA/UFMG), Minas Gerais, Brazil. FBM- Fusarium brachiaria Marandu. Isolates were stored in the Mycological Collection of Lavras (CML) at Federal University of Lavras (UFLA), in Lavras, Minas Gerais, Brazil. Samples were also stored in the Mycological Collection of the Laboratory of Research in Phytopatology from the University of Minas Gerais, Campus Montes Claros, Minas Gerais, Brazil. Morphological Characterization Morphological characterization was performed according Leslie and Summerell ( 2006 ). Isolates were cultivated in Petri plates containing Potato Dextrose Agar (PDA) and incubated at 25 ºC and 12 h photoperiod for 7 days. After this period the growth rate was determined and 10 days after the pigmentation of the colony was verified. Micro-morphologic characteristics such as size and format of micro and macroconidia; shape of phialides; presence of chlamydospores and production of microconidia in chains or false heads were evaluated in Synthetic Nutrient-poor Agar (SNA) at 20ºC, 12 h photoperiod and incubation for 10 to 14 days. To induce the production of micromorphological structures from isolates, sterilized tagetes ( Dianthus caryophyllus L.) leaves were set over 90 mm diameter Petri dishes filled with SNA medium. Two replicates were used for each isolate. DNA extraction, PCR and phylogenetic analysis Fungi isolates were cultivated in a liquid medium based on 2% malt extract for three days at room temperature and constant shaking at 100 rpm. The mycelium was filtered, and ground in liquid nitrogen and the DNA was extracted using the extraction kit Wizard® Genomic DNA Purification (Promega Brazil, São Paulo, BR), following the specifications of the manufacturer. The concentration of DNA was determined using NanoDrop 2000 (Thermo Fisher Scientific Inc., Waltham, USA). Fragments of the elongation factor 1-α , (TEF- 1-α ) gene were amplified using the primers EF 1-F (forward; 5’- ATGGGTAAGGAGGACAAGAC-3’) and EF2-R (reverse; 5’-GGAAGTACCAGTGATCATGTT-3’), described by O’Donnell et al. ( 1998 ) and following the cycle conditions described by O’Donnell et al. ( 2008 ). The electropherograms generated were analyzed and edited using the software SeqAssem ver.07/2008 (SequentiX – Digital DNA Processing, Klein Raden, Germany) (Hepperle 2011 ). The alignments were generated using the tool CLUSTALW (Thompson et al. 1994), implemented by the software MEGA11 (Tamura et al. 2021 ). DNA sequences of species were obtained from the GenBank and added to the alignments. Phylogenetic analyses were performed by the maximum parsimony method (MP) using the software MEGA 11. Reference sequences from the EF-1α region from FFSC species, available in the GenBank, were included in the analyses. Sequences from F . oxysporum (NRRL 22902) and F . inflexum (NRRL 20433) were used as outgroup. Pathogenicity test To assess the pathogenicity of Fusarium spp., the isolates (Table 1 ) were inoculated on 30-day-old, pre-emergence tillers of U. brizantha cultivars Marandu and Xaraés. To obtain the inoculum, isolates were cultivated in 90 mm diameter Petri plates filled with PDA, incubated for seven days at 25 ºC and 12 h photoperiod. After this period, sterile distilled water was added to the plates. Then, the spore solution was adjusted to a concentration of 2.5x 10 6 conidia/mL. To perform plant inoculation, 10 mL of the spore suspension was dripped into the rhizosphere region of the seedlings studied. A pit approximately 5 cm deep was made in the rhizosphere region where the spore solution was dripped and then covered with soil. For each isolate, five seedlings of each cultivar were inoculated. Control treatment consisted of seedlings of cultivars Marandu and Xaraés without inoculation. After inoculation, seedlings remained in a greenhouse under micro-sprinkling irrigation turned on for two minutes and three times a day. The randomized block design (RBD) with five replicates was used, where each treatment consisted of a pot containing Urochloa with two tillers in a factorial 14x2 + 10 (14 isolates of Fusarium spp., 2 cultivars and 2 controls). Two replicate greenhouse experiments were conducted, separated in time and space (two weeks after the first experiment), between the months of September to December 2023. The symptomatology of the disease was evaluated weekly for 42 days (6 weeks), observing the onset of symptoms. Plant disease was confirmed when plants showed symptoms of leaf yellowing, leaf drought, and dead tillers. After 6 weeks, the symptoms of collar rot, rhizome rot, and darkening of vascular tissues were evaluated. A longitudinal incision was made in the plants to observe symptoms. Fragments of diseased plant tissues were disinfected with Ethanol 70% and sodium hypochlorite 1%, followed by triple washing in sterile distilled water. Then, these tissue fragments were transferred to PDA plates to re-isolate the fungus, fulfilling Koch’s postulates. Isolates were considered pathogenic when they produced disease symptoms as previously described. Disease incidence was evaluated after 42 days based on tiller death on cultivars tested using the equation: $$\:I\:\left(\%\right)=\left(\frac{NPM}{NTP}\right)x\:100$$ Where: I (%) = Incidence (in percentage); NDT = number of death tillers; NTP = total number of plants evaluated. Statistical analyses Statistical analyses were performed using the software R, version 4.2.2 (R Development Core Team, 2022). Results Fusarium sp. isolates Fifteen Fusarium isolates were obtained from U. brizantha cv. Marandu from the municipality in the North of Minas Gerais state, Brazil (Table 1 ). Isolates were identified and assembled by morphotypes belonging to the species complex Fusarium fujikuroi (FFSC) and Fusarium oxysporum (FOSC). Phylogenetic analysis The method of Maximum Parsimony (MP) for the EF-1α region (Fig. 1 ) was used to construct the phylogenetic tree of Fusarium sp. isolates obtained from U. brizantha and reference isolates belonging to the F. fujikuroi species complex. The analysis of partial sequences of the EF-1α gene through the MP method resulted in 7 isolates clustered in 4 different clades to the species complex F. fujikuroi (FFSC). Two isolates clustered with the reference isolate F . caapi , and two isolates clustered with F . verticillioides and one with F . proliferatum . Two isolates constituted a separated lineage, described in the present study as Fusarium sp.4. Based on the phylogenetic analysis the seven isolates were selected to perform the pathogenicity test. Morphological characterization of Fusarium species The morphological characteristics of the asexual stage for isolates from the species F . oxysporum, F . verticillioides, F . proliferatum, F . caapi , lineage Fusarium sp.4, and Fusarium sp. were completed according to markers described by Leslie and Summerell ( 2006 ), Costa et al. ( 2021 ), and Laurence et al. ( 2015 ). From 15 isolates obtained of the U. brizantha cv. Marandu, 5 presented the typical morphology of F . oxysporum , 3 were compatible with F . verticillioides , 1 with F . proliferatum , 2 with F . caapi , 2 with the new lineage Fusarium sp.4, and 2 with phylogenetically unidentified Fusarium sp. The isolates produced microconidia in long chains, short chains, and false heads. Fusarium oxysporum is characterized by the production of aggregated microconidia and false heads on short phialides. The microconidia varied from oval, clavate, cylindrical to reniform, with 0.494–0.627 µm and 0–1 septum. Macroconidia showed falcate and almost straight format with foot-shaped basal cell and apical cell in hook-shaped with 6.1–7.5 x 2 µm, and 2–7 septa, with the majority showing 3 septa. Macroconidia were profusely produced in whitish sporodochia and aerial mycelium. The conidiogenous cells were simple, short monophialides with an average of 1.75 µm. Globose chlamydospores with smooth walls formed intercalary in pairs and solitary terminally were observed. All isolates produced aerial, sparse, and cottony mycelium. However, colony pigmentation was variable among isolates CML3882, CML3885, CML3888 and CML3890, varying from dark to light pink, white, purple, wine, and reddish/blue orange. The aerial mycelium varied from white, light purple to purple (Fig. 2 ). In F. verticillioides the formation of microconidia in long chains on monophialides (2.6 x 0.1 µm) was observed in the aerial mycelium. Branched and simple conidiophores in the aerial mycelium were also verified (Fig. 3 ). Microconidia showed an oval to elongated shape with 1.6x 0.58 µm. Macroconidia showed an average size of 9.5 x 1.35 µm. Isolates CML3886, CML3887 and LPF-FBM16 showed sparse, cottony aerial mycelium with cream to light purple coloration. Pigmentation on the back side of the colony showed cream coloration with a light brown halo in the middle. The species F. proliferatum , CML3880 (Fig. 4 ) showed microconidia produced in short chains from polyphialides, varying from golf cue to pear-shaped format, with 1.67 x 0.57 µm, without septum. Macroconidia were 6–8 x 3.5 µm, with 3–5 septa. Chlamydospores were absent. Sparse aerial and cottony mycelium, with a light pink to purple color, was evidenced. Pigmentation on the back side of the colony varied from cream to light pink with a dark pink halo. Morphological characteristics in the sexual F. caapi stage, CML3881 and CML3883 (Fig. 5 ) showed oval to ovoid microconidia with 5–15 x 2–5 µm, with one or without septum, being predominantly septate, produced on false heads or short chains in monophialides and poliphialides measuring 17.5–32.5 x 2–5 µm. Conidiogenous cells were simple or branched conidiophores. Straight and slightly curved macroconidia, apical and basal cells slightly evident, with 3–5 septa, measuring 23.5–55 x 2–5 µm, profuse production of chlamydospores in chains or clusters, terminal or intercalary, globose and cylindrical, measuring 4.5–22.2 x 5-18.5 µm. Cottony mycelia, white to light gray pigmented. Pigmentation on the back side of the colony varied from cream to yellow. The phylogenetic lineage denoted Fusarium sp.4, CML3889 and CML3892 (Fig. 6 ), presents whitish, flocculate-powdery aerial mycelium with cream-colored colonies. Pigmentation on the back side of the colony varied from white to cream. Microconidia are hyaline, ovoid and clavate, with 2-9x1.5-3 µm without septum and 7.5-13.5x2.5-5.5 µm with one septum, produced in false heads and short chains in simple and branched monophialides and polyphialides (17.5-32.5x2-5 µm). Long macroconidia, apical and basal cells slightly evident, with 3–5 septa, predominantly showing 3 septa, with 21-46.5x2.0-5 µm. Chlamydospores in chains were observed, with smooth walls, terminal or intercalated, globose, cylindrical to sub-cylindrical, measuring 4.5-22.2x5-18.5 µm. The isolate LPF-FBM15, identified as Fusarium sp. (Fig. 7 ), showed oval, clavate and ovoid microconidia, measuring 1.4–3.5 x 1.2–1.8 µm, without or with 1 septum, produced in false heads and short chains, in simple and branched monophialides with 5.5–9.4 x 4 µm in length and polyphialides with in 4.4 x 0.880 µm length. Short and cup-shaped philalides were observed, measuring 3.2 x 1.08 µm. Chlamydospores were not observed. Macroconidia showed 2–3 septa, predominantly with 3 septa; 2-septate macroconidia measuring 4.9–9.5 x 1.9–2.3 µm and 3-septate measuring 5.5–12.6 x 2-2.7 µm. Aerial mycelium disperses and floccose with white to cream color. Pigmentation on the back side of the colony is light pink. The isolate LPF-FBM17, identified as Fusarium sp. (Fig. 8 ), produced hyaline microconidia, clavate to ovoid, measuring 1.13–1.3 x 0.59 µm, without or with 1 septum, predominantly without septum, produced in false heads in short chains from simple and branched monophialides or polyphialides (1.4–2.5 x 0.33–0.37 µm). Microconidia aggregated in false heads on short phialides. Macroconidia measuring 5.8 x 1.15 µm. Chlamydospores were observed intercalary. Aerial mycelium sparse and cottony, with white to light pink pigmentation. Pigmentation on the back side of the colony varied from cream to light pink with a pink halo in the center. Pathogenicity test Symptoms started approximately two weeks after soil inoculation. Symptomatology varied between cultivars studied, in a general way resulting in yellowing of the lower leaves in the plant, foliar necrosis and darkening of plant vessels, collar and stalk rot, and death of tillers, but not of the whole plant. The species F . caapi , F . proliferatum , F . verticillioides , the new Fusarium sp.4 lineage, Fusarium sp. (FBM15), Fusarium sp. (FBM17) and F . oxysporum , induced symptoms in plants from cultivars Marandu and Xaraés. Symptoms initiated with yellowing of the lower leaves of the plant progressing to sheath and leaf necrosis. Leaf yellowing started from the apex towards the edges, forming an inverted V shape. In time, the yellowing reached the sheath and leaf base, leading to total leaf drying. Younger leaves showed yellowing advancing to drying of the tillers. In the clump base, stalks, collars and rhizomes showed symptoms of rot. Through a longitudinal cut in the stalk, the discoloration of plant vascular tissues was verified (Fig. 9 ). Isolates from the complex fujikuroi (FFSC) caused stronger rot in the stalks, collars and rhizomes of marandu grass, the isolates from the species F. caapi (CML 3881 and 3883) and isolate FBM17, showed higher incidence when inoculated on cultivar Marandu (83.33%), while in cultivar Xaraés isolates CML 3880 and 3883 showed an incidence of 83.33%. The new lineage Fusarium sp.4 (CML3889 and 3892), had higher incidence in cv. Marandu (66.66%). Isolate CML 3887, representing the species F. verticillioides , showed incidence of 66.66% in both evaluated cultivars, similar to the new lineage Fusarium sp.4 (Table 2 ), according to the incidence percentage equation used in the evaluation. Table 2 Incidence of fusariosis in Marandu and Xaraés cultivars 42 days after inoculation. Isolates Incidence (%) 1 Marandu Xaraés CML3880 50.00 83.33 CML3881 83.33 16.66 CML3882 33.33 66.66 CML3883 83.33 83.33 CML3885 50.00 50.00 CML3888 66.66 50.00 CML3886 33.33 66.66 CML3887 66.66 66.66 CML3890 66.66 33.33 CML3889 66.66 50.00 CML3892 66.66 50.00 FBM15 66.66 16.66 FBM16 50.00 33.33 FBM17 83.33 50.00 1 Results from two experiments were similar and were combined. Values in the table are the means of 10 replicate pots. Thus, cv. Marandu and cv. Xaraés showed symptoms of the disease in tillers inoculated with Fusarium spp. However, the symptoms described above were also observed in cv. Xaraés (Fig. 10 ). The symptoms were more evident in rhizomes than in roots, with slight darkening of the root system being observed. We did not verify a characteristic symptom for a determined Fusarium sp. species. From these infected tissues, the isolates were re-isolated and showed the same morphologic characteristics as the inoculated fungi, thus fulfilling Koch’s postulates (Amorim et al., 2011 ). Control plants showed no symptoms of the disease. Discussion The phylogenetic analysis of the EF-1α gene allowed for the identification of three already known and one new species belonging to the Fusarium fujikuroi species complex (FFSC). Although, some isolates were identified morphologically as being similar to F. oxysporum (FOSC) and the species complex F. incarnatum - equiseti (FIESC). Additionally, two isolates were identified solely through morphological characteristics, exhibiting the morphotype of F. proliferatum . In the present study, we verified Urochloa hosts a variety of Fusarium species. A constant presence of species belonging to the FFCS complex in cv. Marandu and the affinity of this complex for grasses were verified. The species complex F. fujikuroi was predominant among the isolates obtained from U. brizantha cv. Marandu showing symptoms of fusariosis. Fusarium proliferatum , F . caapi , F . verticillioides , a new lineage designated as Fusarium sp.4 and two isolates here nominated as Fusarium sp., were identified. The new Fusarium sp.4 lineage is here called F . “ buritiense ”. All these isolates were obtained from the municipality of Buritizeiro, North of Minas Gerais state, Brazil (Table 1 ). Burgess and Summerell ( 1992 ) verified diverse Fusarium species in native grass areas in Australia. In Kenya, different Fusarium species were identified as endophytes associated with forages from the genus Urochloa (Kago et al. 2016 ). Based on phylogenetic analysis of the EF-1α gene region, using the Maximum Parsimony method, two isolates were identified as F. caapi. This new species is closely related to F. mundagurra , belongs to the African clade, according to the theory proposed in the phylogeographic evidence of FFSC species (O’Donnell et al. 1998 ). In short, the genus Urochloa has its center of origin in the African continent. There is difficulty in discriminating the new phylogenetic lineage Fusarium sp. from F . mundagurra , F . caapi and F . proliferatum based only on their morphological characterization, once all species produce conidia in short chains on phialides. Isolates of Fusarium sp.4 (CML3889 and CML3892), produced clavate conidia, being the most usual format when compared to oval and ovoid conidia. These two last conidia formats were commonly observed in isolates of the species F . caapi (CML3881 and CML3883) and species F . brachiariae and F . mundagurra , described in studies by Laurence et al. ( 2015 ) and Costa et al. ( 2021 ). Production of chlamydospores was observed in isolates of Fusarium sp.4, as also described in F . caapi , discriminating them from F. proliferatum in which chlamydospores are absent. Isolates CML3881 and CML3883, clustered to the clade of the species F. caapi . This species was reported for the first time in U. brizantha seeds from different regions in Brazil, belonging to the African clade and constituting a brother group of F . mundagurra (Costa et al. 2021 ). Morphological characteristics of F . proliferatum are also observed in F . fujikuroi , F. lactis and F . phyllophilum , once all produce microconidia in short chains on polyphialides (Nirenberg et al. 1998; Leslie and Summerell 2006 ). Yet, phylogenetic analysis can discriminate this species from each other. The isolate CML3880 clustered to the clade of F. proliferatum , constituting an internal group with F. fujikuroi. A morphologic marker of F . verticillioides is the production of microconidia in long chains on monophialides (Klittich et al. 1997 ; Marasas et al. 2001 ; Leslie and Summerell 2006 ). This characteristic was observed in isolates CML3886, CML3887 and FBM16. Nevertheless, only the first two isolates were sequenced and phylogenetically analyzed. F . verticillioides has a wide world distribution, has a close association with maize and can cause stalk and ear rot (Leslie and Summerell 2006 ). Based on morphological characteristics, we believe that isolates FBM15 and FBM17 (Fusarium sp.) belong to the FFSC, due to the production of conidia in short chains on mono and polyphyalides. These are characteristics observed in F . mundagurra, F . caapi , F . brachiariae and F . nygamai (Burgess and Trimboli 1986 ; Laurence et al. 2015 ; Costa et al. 2021 ). Morphological markers of F. oxysporum were observed in isolates FBM3, FBM6, FBM7 and FBM10. The species complex FOSC is characterized by the production of microconidia aggregated in false heads on short phialides (Gerlach and Nirenberg 1982 ; Leslie and Summerell 2006 ). In the present study, inoculation tests revealed that isolates caused typical rotting symptoms of FFSC in cultivars Marandu and Xaraés. Initial symptoms were yellowing of leaves and sheath, with the latter dry and death of some tillers, symptoms observed in species of Fusarium sp. infecting some grass species and chickpea (Leslie and Summerell 2006 ; Singh et al. 2007 ). The species F . proliferatum was already reported as pathogenic in sugarcane, producing symptoms of stalk rot in maize, sorghum and pearl millet, and producing mycotoxins in maize grains (Nordahliawate et al. 2008; Zhang et al. 2012 ; Costa et al. 2019 ). In the present study, the species F. oxysporum produced disease symptoms in some tillers of both U. brizantha cultivars, although this species has already been isolated as endophytic in Urochloa seeds from various countries such as Kenya, Ethiopia and Burundi (Teasdale et al. 2019). In Central and South America and countries where banana and leguminous plants such as chickpeas are cultivated, the F. oxysporum complex has caused pronounced economic losses (Ploetz 2006 ; Singh et al 2007 ; Ploetz 2015 ). Zúñiga Pereira et al. (1998) studied four species belonging to the genus Urochloa , including the cv. Marandu identified fungi of the genus Fusarium causing symptoms in U. brizantha cv. Marandu under field capacity conditions, as well as plant death 24 days after inoculation of Fusarium isolates. Marchi et al. ( 2006 ) studied the pathosystem Fusarium sp. x Urochloa brizantha and Panicun maximum , verifying mild symptoms with yellowing leaves, while in cv. Massai the symptoms were stronger, followed by plant dryness and death. Spores or mycelium of the genus Fusarium may infect plant roots, directly through intact tissues or through root wounds or in secondary roots under development, causing the host disease or death (Leslie and Summerell 2006 ; Singh et al. 2007 ). After a longitudinal incision on the plant stalk, vascular discoloration, necrosis of internal tissues and tissue rot, were observed. As plants grow older, in addition to the yellowing leaves and sheath, stalk, collar, and rhizome rot develop. A signal of the fungus potential to systemically colonize the forage. Species of the FFSC show a high capacity to infect forages of the genus Urochloa , this may become a problem for the introduction and establishment of some grass species in areas with previous reports of the disease. We identified for the first time pathogenic species of Fusarium to Urochloa brizantha cv. Marandu also reported a new strain of Fusarium sp.4 in Marandu grass in Brazil. Urochloa brizantha cv. Marandu may act as a source of inoculum for species within FFSC and FOSC, predominantly species from the F . fujikuroi complex. The species F. caapi , F. verticillioides , Fusarium sp.4, F. oxysporum , F. proliferatum , and the isolates FBM17 and FBM15 ( Fusarium sp.) were pathogenic and aggressive to both cvs. Marandu and Xaraés. Morphological markers cannot be the only tool for distinguishing species of F . fujikuroi complex. Declarations Acknowledgements The first author wishes to thank CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for the scholarship and FAPEMIG (Fundação de Amparo à Pesquisa do Estado de Minas Gerais), APQ-00472-22, for financial support. The authors would also like to thank the Universidade Federal de Minas Gerais for its technical support and infrastructure, as well as the Plant Pathology team (GEFIT-UFMG). Authors’ contribution Conceptualization: FSR and FLA; Methodology: FSR, FLA, and MFGF; Formal analysis and invetigation: FLA, MFGF, MMC; Writing-original draft preparation; FLA and FSR; Writing-review, and editing: GLDL, JMAR and LHP; Funding acquisition: FSR and LHP; Resources: FLA, MMC, LHP and FSR; Supervision: FSR. Funding Not applicable. Data availability The data analyzed in this research is available from the corresponding author upon reasonable request. Ethics declaration Not applicable. Conflict of interest The authors declare no conflict of interest. References Amorim L, Rezende JAR, Bergamin Filho A (Eds.) (2011) Manual de Fitopatologia. Vol.1. Princípios e Conceitos. 4 Ed. Ceres, São Paulo Bentley AR, Petrovic T, Griffiths SP, Burgess LW, Summerell BA (2007) Crop pathogens and other Fusarium species associated with Austrostipa aristiglumis . Australasian Plant Pathology 36:434-438 doi.org/10.1071/ap07047 Burgess LW, Summerell BA (1992) Mycogeography of Fusarium . 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Journal of the Science of Food and Agriculture 93:693-701 doi.org/10.1002/jsfa.5794 Zúñiga PC, González QR, Bustamante E, Argel P (1998) Influencia de la humedad del suelo sobre la susceptibilidad de Brachiaria a hongos patógenos. Manejo Integrado de Plagas 49:51-57. Available at: https://repositorio.catie.ac.cr/handle/11554/7447?show=full (last checked 25 Jul 2023) Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revisions 04 Sep, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers invited by journal 31 Jul, 2025 Editor invited by journal 31 Jul, 2025 Editor assigned by journal 31 Jul, 2025 First submitted to journal 25 Jul, 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. 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Lengths of the branches are shown by the scale in the base of the tree and the values of the statistical support are shown above the nodes. Abbreviations of culture collections: CML: Mycological Collection of Lavras; CBS: Centraalbureau voor Schimmelcultures, Utrecht, Holanda; MUCL: Mycothe`que de l’Universite; NRRL: Northern Regional Research Laboratory; RBG Royal Botanic Gardens Trust, Sydney, New South Wales, Australia.\u003c/p\u003e","description":"","filename":"Fig1.ArvoreMPtefFus.BrachiaFernando090123.png","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/8c5c24b27624c5bc491adeb4.png"},{"id":88362852,"identity":"5e41764d-a46a-4561-ab72-7ec7b224f7ff","added_by":"auto","created_at":"2025-08-05 16:45:31","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2884473,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium oxysporum\u003c/em\u003easexual stage. \u003cstrong\u003ea\u003c/strong\u003e. Microconidia aggregated in false heads.\u003cstrong\u003e b. \u003c/strong\u003eFalse heads are bottle-shaped.\u003cstrong\u003e c,e. \u003c/strong\u003eMicroconidia. \u003cstrong\u003ed. \u003c/strong\u003eMacroconidia. \u003cstrong\u003ef\u003c/strong\u003e. Chlamidospores. \u003cstrong\u003eg\u003c/strong\u003e. Macroconidia in aerial mycelium. \u003cstrong\u003eh.\u003c/strong\u003eSporodochium formed in clove leaf grown on SNA medium. \u003cstrong\u003ei,l\u003c/strong\u003e. Color of mycelium grown in PDA medium. \u003cstrong\u003ei.-k\u003c/strong\u003e. Obverse. \u003cstrong\u003ej,l.\u003c/strong\u003eReverse. Scale bar: \u003cstrong\u003ea-f\u003c/strong\u003e= 2 µm and \u003cstrong\u003eg\u003c/strong\u003e=\u003cstrong\u003e \u003c/strong\u003e10 µm.\u003c/p\u003e","description":"","filename":"Fig.2Foxysporum1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/aeb1724d2f9e03a4c51c34a1.jpg"},{"id":88363447,"identity":"03444c7f-22de-4294-bf0e-709c929b67bd","added_by":"auto","created_at":"2025-08-05 16:53:31","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":8606013,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium verticillioides\u003c/em\u003e asexual stage. \u003cstrong\u003ea-c\u003c/strong\u003e. Microconidia in long chains. \u003cstrong\u003ed.e.\u003c/strong\u003eMonophialides. \u003cstrong\u003ef\u003c/strong\u003e. Monophialide in “rabbit ear” shape. \u003cstrong\u003eg.h.\u003c/strong\u003eMicroconidia. \u003cstrong\u003ei. l\u003c/strong\u003e. Color of mycelium grown in PDA medium. \u003cstrong\u003ei.k\u003c/strong\u003e. Obverse. \u003cstrong\u003ej.l.\u003c/strong\u003e Reverse. Scale bar: \u003cstrong\u003ea\u003c/strong\u003e= 20 µm and \u003cstrong\u003eb-h\u003c/strong\u003e= 2 µm.\u003c/p\u003e","description":"","filename":"Fig.3Fverticillioides1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/5228d557f0f56e0a1d980bcb.jpg"},{"id":88363451,"identity":"672ad99e-4d38-4009-833c-6040822ea779","added_by":"auto","created_at":"2025-08-05 16:53:31","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":7514767,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium\u003c/em\u003e \u003cem\u003eproliferatum\u003c/em\u003e asexual stage. \u003cstrong\u003ea-b.\u003c/strong\u003e Microconidia in short chains on polyphialides. \u003cstrong\u003ec.d.\u003c/strong\u003e Monophyalides. \u003cstrong\u003ee. \u003c/strong\u003eMacroconidia. \u003cstrong\u003ef.g.\u003c/strong\u003eMicroconidia. \u003cstrong\u003eh.i.\u003c/strong\u003e Obverse and reverse of the colony in PDA medium. Scale bar: \u003cstrong\u003ea-b\u003c/strong\u003e= 20 µm and \u003cstrong\u003ec-g\u003c/strong\u003e= 2 µm.\u003c/p\u003e","description":"","filename":"Fig.4Fproliferatum1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/6b4dba50572cf883ce27d77a.jpg"},{"id":88362853,"identity":"2212c28d-6bde-4967-993c-b8c68faaebf5","added_by":"auto","created_at":"2025-08-05 16:45:31","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":7077243,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium\u003c/em\u003e \u003cem\u003ecaapi\u003c/em\u003e asexual stage. \u003cstrong\u003ea.b.c.\u003c/strong\u003eMicroconidia in short chains. \u003cstrong\u003ed. \u003c/strong\u003eMicroconidia in chain formed on polyphialide. \u003cstrong\u003ee.f.\u003c/strong\u003e Monophialide.\u003cstrong\u003e g\u003c/strong\u003e. Microconidia 0-septum. \u003cstrong\u003eh.\u003c/strong\u003eMacroconidia. \u003cstrong\u003ei,j.\u003c/strong\u003e Chlamidospores. \u003cstrong\u003ek.l.m.\u003c/strong\u003e Color of mycelium grown in PDA medium. \u003cstrong\u003ek.l.\u003c/strong\u003e Obverse. m Reverse. Scale bar: \u003cstrong\u003ea-j\u003c/strong\u003e= 2 µm.\u003c/p\u003e","description":"","filename":"Fig.5Fcaapi1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/f401a1580098937e08e95ff2.jpg"},{"id":88362856,"identity":"914afbbb-003d-4be5-a208-d51ce32067ee","added_by":"auto","created_at":"2025-08-05 16:45:31","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":8469714,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium\u003c/em\u003e sp.4 asexual stage. \u003cstrong\u003ea.b.d. \u003c/strong\u003eMonophialides. \u003cstrong\u003ec. \u003c/strong\u003eMicroconidia in short chain. \u003cstrong\u003ee. \u003c/strong\u003ePolyphialide. \u003cstrong\u003ef.\u003c/strong\u003eMicroconidia in polyphialide. \u003cstrong\u003eg. \u003c/strong\u003eMicroconidia with 0-1 septum. \u003cstrong\u003eh.\u003c/strong\u003eSporodochium formed in clove leaf in SNA medium. \u003cstrong\u003ei.\u003c/strong\u003e Macroconidia with 3 septa. \u003cstrong\u003ej. k\u003c/strong\u003e. Clamidósporos intercalar e terminal. \u003cstrong\u003el.m.\u003c/strong\u003e Color of mycelium grown in PDA medium. \u003cstrong\u003el.\u003c/strong\u003e Obverse. \u003cstrong\u003em.\u003c/strong\u003e Reverse. Scale bar: \u003cstrong\u003ea-f.-i\u003c/strong\u003e= 2 µm and \u003cstrong\u003ej.k\u003c/strong\u003e= 10 µm.\u003c/p\u003e","description":"","filename":"Fig.6Fusariumsp.41.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/d3caa8eddf1da0cbc146ea28.jpg"},{"id":88363448,"identity":"a8f85dfa-f720-4018-b5c3-05c2606d9a64","added_by":"auto","created_at":"2025-08-05 16:53:31","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":7624695,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium\u003c/em\u003e sp. (LPF-FBM15) asexual stage \u003cstrong\u003ea.b. \u003c/strong\u003eMicroconidia in polyphialides. \u003cstrong\u003ec.\u003c/strong\u003e Polyphialide. \u003cstrong\u003ed.e.\u003c/strong\u003e Microconidia in short chain. \u003cstrong\u003ef.\u003c/strong\u003e Monophyalide. \u003cstrong\u003eg. \u003c/strong\u003eMacroconidia with 2-3 septa. \u003cstrong\u003eh.\u003c/strong\u003eMicrocomidia. \u003cstrong\u003ei-l.\u003c/strong\u003e Color of mycelium grown in PDA medium. \u003cstrong\u003ei.k.\u003c/strong\u003eObverse. \u003cstrong\u003ej.l.\u003c/strong\u003e Reverse. Scale bar: \u003cstrong\u003ea-b\u003c/strong\u003e= 20 µm and \u003cstrong\u003ec-h\u003c/strong\u003e= 2 µm.\u003c/p\u003e","description":"","filename":"Fig.7FBM151.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/acf374e1d0cf5fe05a918637.jpg"},{"id":88362863,"identity":"d270e4ad-e626-45f3-a346-4594955179eb","added_by":"auto","created_at":"2025-08-05 16:45:31","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":6428207,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological characteristics of \u003cem\u003eFusarium\u003c/em\u003e sp. (LPF-FBM17) asexual stage. \u003cstrong\u003ea. \u003c/strong\u003eMonophialide.\u003cstrong\u003e b.c.\u003c/strong\u003eMicroconidia in short chain. \u003cstrong\u003ed.f. \u003c/strong\u003eMicroconidia. \u003cstrong\u003ee. \u003c/strong\u003eMicrocomnidia in polyphialides. \u003cstrong\u003eg.h.\u003c/strong\u003e Microconidia aggregated in short false heads. \u003cstrong\u003ei.j.\u003c/strong\u003eMacroconidia. \u003cstrong\u003ek. \u003c/strong\u003eChlamidospores. \u003cstrong\u003el.m.\u003c/strong\u003e Color of mycelium grown on PDA medium. \u003cstrong\u003ei.\u003c/strong\u003e Obverse. \u003cstrong\u003em.\u003c/strong\u003e Reverse. Scale bar: \u003cstrong\u003ea-k\u003c/strong\u003e= 2 µm.\u003c/p\u003e","description":"","filename":"Fig.8FBM171.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/3b613dfd64b733b3361f273d.jpg"},{"id":88363450,"identity":"010c9f50-5427-46e7-baff-5095585e466e","added_by":"auto","created_at":"2025-08-05 16:53:31","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":7167077,"visible":true,"origin":"","legend":"\u003cp\u003eSymptoms of fusariosis in marandu grass. \u003cstrong\u003ea.\u003c/strong\u003e Contol without symptoms. \u003cstrong\u003eb.\u003c/strong\u003eplants with symptoms of yellowing and leaf and sheath necrosis. \u003cstrong\u003ec.d.e.f.g.h. \u003c/strong\u003eSymptoms induced by species of the FFSC complex. \u003cstrong\u003ei.j.k.\u003c/strong\u003e Symptoms caused by \u003cem\u003eFusarium oxysporum\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Fig.10.png","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/396cbb5cbcc3ef9bc3ab128f.png"},{"id":88362862,"identity":"cb5627ad-f32f-4544-a474-0e5dc8ef0a03","added_by":"auto","created_at":"2025-08-05 16:45:31","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":6126630,"visible":true,"origin":"","legend":"\u003cp\u003eSymptoms of fusariosis in cv. Xaraés. \u003cstrong\u003ea. \u003c/strong\u003eControl without symptoms. \u003cstrong\u003eb.\u003c/strong\u003e plants with symptoms of yellowing and leaf and sheath necrosis.\u003cstrong\u003e c.d.e.f.g.\u003c/strong\u003eSymptoms induced by species of the FFSC complex. \u003cstrong\u003eh.i.j.\u003c/strong\u003e Symptoms caused by \u003cem\u003eFusarium oxysporum\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Fig.11.png","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/0d09154135a52c9d4e47c7cb.png"},{"id":88364645,"identity":"ba8d4568-bf0b-4586-bea7-3d3793c7b958","added_by":"auto","created_at":"2025-08-05 17:10:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":75633479,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7188016/v1/e534069a-7ecb-41be-899e-f3843e6501eb.pdf"}],"financialInterests":"","formattedTitle":"Fusarium species pathogenic to Urochloa brizantha in the north de Minas Gerais, Brazil","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe genus \u003cem\u003eUrochloa\u003c/em\u003e (sin. \u003cem\u003eBrachiaria\u003c/em\u003e) originated in Africa and propagates through seeds, being extensively cultivated as a forage plant due to its adaptability to average fertility soils. Being native to the African continent, it possesses high potential for adaptability to the Brazilian tropical climate and soils from the Cerrado (Nunes et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1984\u003c/span\u003e; Lorenzi \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). The area occupied by the pasture was 164.57\u0026nbsp;million hectares in 2023, representing 19.35% of land used for livestock (MapBioma 2023). \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu was implemented in Brazil in 1984, being cultivated mainly in the North and Central West regions. However, since the 1990s, reports of the sudden death disease causing the degradation of grassland areas in Brazil have arisen. The disease was associated with abiotic variables (environmental factors) and primarily with biotic factors such as \u003cem\u003ePythium perillum\u003c/em\u003e, \u003cem\u003eFusarium\u003c/em\u003e sp. and \u003cem\u003eRhizoctonia solani\u003c/em\u003e (Z\u0026uacute;\u0026ntilde;iga et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Duarte et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), which causes collar rot in this forage plant. In the northern region of the state of Minas Gerais, Brazil, there were also reports of grasslands death exhibiting similar symptoms as in the previously mentioned regions.\u003c/p\u003e\u003cp\u003e\u003cem\u003eFusarium\u003c/em\u003e species may modify the plant physiology by producing various mycotoxins which are detrimental to their hosts (Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Their main characteristic is the production of elongated, fusiform, septate conidia (Gerlach and Nirenberg \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1982\u003c/span\u003e). \u003cem\u003eFusarium\u003c/em\u003e species may behave as pathogens, saprophytes or endophytes, depending on the host and the environmental conditions (Bentley et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Summerell et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). One of the earliest studies associating \u003cem\u003eFusarium\u003c/em\u003e species with native grasses and cultivated plants occurred in Australia (Burgess 1988; Burgess and Summerell \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1992\u003c/span\u003e). This genus was obtained from samples of vegetal residues and soils, as well as from host plants within natural pathosystems (Burgess and Summerell \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Laurence et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSpecies of the \u003cem\u003efujikuroi\u003c/em\u003e complex are amongst the most common diseases in crops of economic prominence. In Asia, various species from this complex were described, such as \u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003esacchari\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e and \u003cem\u003eF. fujikuroi\u003c/em\u003e, causing diseases in rice, sugar-cane and corn (Hsuan et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Although \u003cem\u003eF. sacchari\u003c/em\u003e is considered an endophytic fungus in \u003cem\u003eOryza australiensis\u003c/em\u003e, better known as wild rice in Australia, it is the main causal agent of the \u003cem\u003epokkah boeng\u003c/em\u003e disease in sugarcane (Petrovic et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In addition, \u003cem\u003eF. madaense\u003c/em\u003e, \u003cem\u003eF. andyazi\u003c/em\u003e and \u003cem\u003eFusarium mirum\u003c/em\u003e were associated with grasses of agricultural importance in Africa and Brazil (Costa et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). As well as \u003cem\u003eF. circinatum\u003c/em\u003e causing canker in \u003cem\u003ePinus\u003c/em\u003e sp., which is disseminated in many countries, including Brazil, and is an important disease problem in forestry (Wingfield et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Steenkamp et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Pfenning et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2014\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eMany fungi species were described as endophytic in forages from the genus \u003cem\u003eUrochloa\u003c/em\u003e in Kenya, the genus \u003cem\u003eFusarium\u003c/em\u003e being the most abundant in the radicular system of these plants (Kago et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). A study based on phylogenetic analysis in Brazil revealed two new species: \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ebrachiariae\u003c/em\u003e, belonging to the African clade of the species complex \u003cem\u003eFusarium fujikuroi\u003c/em\u003e (FFSC), sharing the main morphological characteristics with \u003cem\u003eF\u003c/em\u003e. \u003cem\u003emundagurra\u003c/em\u003e and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003enygamai\u003c/em\u003e. These two new species were isolated from \u003cem\u003eU. brizantha\u003c/em\u003e and \u003cem\u003eU. decumbens\u003c/em\u003e asymptomatic seeds (Costa et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, many species from the \u003cem\u003eF. fujikuroi\u003c/em\u003e complex have a preference for grasses, surviving as endophytes or causing diseases (Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Costa et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTherefore, native and cultivated grasses may host a great diversity of pathogenic species. Additionally, these pathosystems may also host news \u003cem\u003eFusarium\u003c/em\u003e species. Hence, we aimed to identify \u003cem\u003eFusarium\u003c/em\u003e species associated with marandu grass in municipalities from the North of Minas Gerais state, Brazil, and to test the pathogenicity of these isolates to \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu and Xara\u0026eacute;s.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cb\u003eIsolates of\u003c/b\u003e \u003cb\u003eFusarium\u003c/b\u003e \u003cb\u003esp.\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe isolates used in the present study were obtained from monosporic cultures from typical cultures of the genus \u003cem\u003eFusarium\u003c/em\u003e, obtained from disinfected tissues (70% ethanol and 1% sodium hypochlorite) of \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu. In order to obtain the isolates, small fragments of plant tissues exhibiting symptoms of leaf yellowing and drought of the aerial portion (sudden death) were used. Samples were collected in the field in the municipality of Buritizeiro, located in the northern region of Minas Gerais, Brazil, to obtain fungal isolates (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eIsolates of Fusarium sp. obtained from marandu grass plants (Urochloa brizantha cv. Marandu) in the municipality of Buritizeiro, MG, Brazil.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSpecies\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCode\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eGeographic Origin\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHost\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML3880\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3881\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3882\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3883\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3885\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3886\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF. verticillioides\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3887\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3888\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eFusarium\u003c/em\u003e sp.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3889\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3890\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eFusarium\u003c/em\u003e sp.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3892\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCML 3896\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eFusarium sp.\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLPF-FBM15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLPF-FBM16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eFusarium sp.\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLPF-FBM17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBuritizeiro-MG\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eU. brizantha\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e\u003cp\u003eCML \u0026ndash; Mycological Collection of Lavras, Departament of Phytopathology, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil.\u003c/p\u003e\u003cp\u003eLPF \u0026ndash; Laboratory of Phytopathology Research, Universidade de Minas Gerais (ICA/UFMG), Minas Gerais, Brazil.\u003c/p\u003e\u003cp\u003eFBM- \u003cem\u003eFusarium brachiaria\u003c/em\u003e Marandu.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eIsolates were stored in the Mycological Collection of Lavras (CML) at Federal University of Lavras (UFLA), in Lavras, Minas Gerais, Brazil. Samples were also stored in the Mycological Collection of the Laboratory of Research in Phytopatology from the University of Minas Gerais, \u003cem\u003eCampus\u003c/em\u003e Montes Claros, Minas Gerais, Brazil.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMorphological Characterization\u003c/b\u003e\u003c/p\u003e\u003cp\u003eMorphological characterization was performed according Leslie and Summerell (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Isolates were cultivated in Petri plates containing Potato Dextrose Agar (PDA) and incubated at 25 \u0026ordm;C and 12 h photoperiod for 7 days. After this period the growth rate was determined and 10 days after the pigmentation of the colony was verified. Micro-morphologic characteristics such as size and format of micro and macroconidia; shape of phialides; presence of chlamydospores and production of microconidia in chains or false heads were evaluated in \u003cem\u003eSynthetic Nutrient-poor Agar\u003c/em\u003e (SNA) at 20\u0026ordm;C, 12 h photoperiod and incubation for 10 to 14 days. To induce the production of micromorphological structures from isolates, sterilized tagetes (\u003cem\u003eDianthus caryophyllus\u003c/em\u003e L.) leaves were set over 90 mm diameter Petri dishes filled with SNA medium. Two replicates were used for each isolate.\u003c/p\u003e\u003cp\u003e\u003cb\u003eDNA extraction, PCR and phylogenetic analysis\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFungi isolates were cultivated in a liquid medium based on 2% malt extract for three days at room temperature and constant shaking at 100 rpm. The mycelium was filtered, and ground in liquid nitrogen and the DNA was extracted using the extraction kit Wizard\u0026reg; Genomic DNA Purification (Promega Brazil, S\u0026atilde;o Paulo, BR), following the specifications of the manufacturer.\u003c/p\u003e\u003cp\u003eThe concentration of DNA was determined using NanoDrop 2000 (Thermo Fisher Scientific Inc., Waltham, USA). Fragments of the \u003cem\u003eelongation factor 1-α\u003c/em\u003e, (TEF-\u003cem\u003e1-α\u003c/em\u003e) gene were amplified using the primers \u003cem\u003eEF\u003c/em\u003e1-F (forward; 5\u0026rsquo;- ATGGGTAAGGAGGACAAGAC-3\u0026rsquo;) and EF2-R (reverse; 5\u0026rsquo;-GGAAGTACCAGTGATCATGTT-3\u0026rsquo;), described by O\u0026rsquo;Donnell et al. (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1998\u003c/span\u003e) and following the cycle conditions described by O\u0026rsquo;Donnell et al. (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). The electropherograms generated were analyzed and edited using the software SeqAssem ver.07/2008 (SequentiX \u0026ndash; Digital DNA Processing, Klein Raden, Germany) (Hepperle \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The alignments were generated using the tool CLUSTALW (Thompson et al. 1994), implemented by the software MEGA11 (Tamura et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). DNA sequences of species were obtained from the GenBank and added to the alignments.\u003c/p\u003e\u003cp\u003ePhylogenetic analyses were performed by the maximum parsimony method (MP) using the software MEGA 11. Reference sequences from the \u003cem\u003eEF-1α\u003c/em\u003e region from FFSC species, available in the GenBank, were included in the analyses. Sequences from \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e (NRRL 22902) and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003einflexum\u003c/em\u003e (NRRL 20433) were used as outgroup.\u003c/p\u003e\u003cp\u003e\u003cb\u003ePathogenicity test\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTo assess the pathogenicity of \u003cem\u003eFusarium\u003c/em\u003e spp., the isolates (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) were inoculated on 30-day-old, pre-emergence tillers of \u003cem\u003eU. brizantha\u003c/em\u003e cultivars Marandu and Xara\u0026eacute;s. To obtain the inoculum, isolates were cultivated in 90 mm diameter Petri plates filled with PDA, incubated for seven days at 25 \u0026ordm;C and 12 h photoperiod. After this period, sterile distilled water was added to the plates. Then, the spore solution was adjusted to a concentration of 2.5x 10\u003csup\u003e6\u003c/sup\u003e conidia/mL.\u003c/p\u003e\u003cp\u003eTo perform plant inoculation, 10 mL of the spore suspension was dripped into the rhizosphere region of the seedlings studied. A pit approximately 5 cm deep was made in the rhizosphere region where the spore solution was dripped and then covered with soil. For each isolate, five seedlings of each cultivar were inoculated. Control treatment consisted of seedlings of cultivars Marandu and Xara\u0026eacute;s without inoculation. After inoculation, seedlings remained in a greenhouse under micro-sprinkling irrigation turned on for two minutes and three times a day. The randomized block design (RBD) with five replicates was used, where each treatment consisted of a pot containing \u003cem\u003eUrochloa\u003c/em\u003e with two tillers in a factorial 14x2\u0026thinsp;+\u0026thinsp;10 (14 isolates of \u003cem\u003eFusarium\u003c/em\u003e spp., 2 cultivars and 2 controls). Two replicate greenhouse experiments were conducted, separated in time and space (two weeks after the first experiment), between the months of September to December 2023.\u003c/p\u003e\u003cp\u003eThe symptomatology of the disease was evaluated weekly for 42 days (6 weeks), observing the onset of symptoms. Plant disease was confirmed when plants showed symptoms of leaf yellowing, leaf drought, and dead tillers. After 6 weeks, the symptoms of collar rot, rhizome rot, and darkening of vascular tissues were evaluated. A longitudinal incision was made in the plants to observe symptoms. Fragments of diseased plant tissues were disinfected with Ethanol 70% and sodium hypochlorite 1%, followed by triple washing in sterile distilled water. Then, these tissue fragments were transferred to PDA plates to re-isolate the fungus, fulfilling Koch\u0026rsquo;s postulates. Isolates were considered pathogenic when they produced disease symptoms as previously described. Disease incidence was evaluated after 42 days based on tiller death on cultivars tested using the equation:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:I\\:\\left(\\%\\right)=\\left(\\frac{NPM}{NTP}\\right)x\\:100$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWhere: I (%)\u0026thinsp;=\u0026thinsp;Incidence (in percentage); NDT\u0026thinsp;=\u0026thinsp;number of death tillers; NTP\u0026thinsp;=\u0026thinsp;total number of plants evaluated.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistical analyses\u003c/b\u003e\u003c/p\u003e\u003cp\u003eStatistical analyses were performed using the software R, version 4.2.2 (R Development Core Team, 2022).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cb\u003eFusarium\u003c/b\u003e \u003cb\u003esp.\u003c/b\u003e \u003cb\u003eisolates\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFifteen \u003cem\u003eFusarium\u003c/em\u003e isolates were obtained from \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu from the municipality in the North of Minas Gerais state, Brazil (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Isolates were identified and assembled by morphotypes belonging to the species complex \u003cem\u003eFusarium fujikuroi\u003c/em\u003e (FFSC) and \u003cem\u003eFusarium oxysporum\u003c/em\u003e (FOSC).\u003c/p\u003e\u003cp\u003e\u003cb\u003ePhylogenetic analysis\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe method of Maximum Parsimony (MP) for the \u003cem\u003eEF-1α\u003c/em\u003e region (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) was used to construct the phylogenetic tree of \u003cem\u003eFusarium\u003c/em\u003e sp. isolates obtained from \u003cem\u003eU. brizantha\u003c/em\u003e and reference isolates belonging to the \u003cem\u003eF. fujikuroi\u003c/em\u003e species complex.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe analysis of partial sequences of the \u003cem\u003eEF-1α\u003c/em\u003e gene through the MP method resulted in 7 isolates clustered in 4 different clades to the species complex \u003cem\u003eF. fujikuroi\u003c/em\u003e (FFSC). Two isolates clustered with the reference isolate \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, and two isolates clustered with\u003c/p\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e and one with \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e. Two isolates constituted a separated lineage, described in the present study as \u003cem\u003eFusarium\u003c/em\u003e sp.4. Based on the phylogenetic analysis the seven isolates were selected to perform the pathogenicity test.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMorphological characterization of Fusarium species\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe morphological characteristics of the asexual stage for isolates from the species \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum, F\u003c/em\u003e. \u003cem\u003everticillioides, F\u003c/em\u003e. \u003cem\u003eproliferatum, F\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, lineage \u003cem\u003eFusarium\u003c/em\u003e sp.4, and \u003cem\u003eFusarium\u003c/em\u003e sp. were completed according to markers described by Leslie and Summerell (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), Costa et al. (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), and Laurence et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). From 15 isolates obtained of the \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu, 5 presented the typical morphology of \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e, 3 were compatible with \u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e, 1 with \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e, 2 with \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, 2 with the new lineage \u003cem\u003eFusarium\u003c/em\u003e sp.4, and 2 with phylogenetically unidentified \u003cem\u003eFusarium\u003c/em\u003e sp. The isolates produced microconidia in long chains, short chains, and false heads.\u003c/p\u003e\u003cp\u003e\u003cem\u003eFusarium oxysporum\u003c/em\u003e is characterized by the production of aggregated microconidia and false heads on short phialides. The microconidia varied from oval, clavate, cylindrical to reniform, with 0.494\u0026ndash;0.627 \u0026micro;m and 0\u0026ndash;1 septum. Macroconidia showed falcate and almost straight format with foot-shaped basal cell and apical cell in hook-shaped with 6.1\u0026ndash;7.5 x 2 \u0026micro;m, and 2\u0026ndash;7 septa, with the majority showing 3 septa. Macroconidia were profusely produced in whitish sporodochia and aerial mycelium. The conidiogenous cells were simple, short monophialides with an average of 1.75 \u0026micro;m. Globose chlamydospores with smooth walls formed intercalary in pairs and solitary terminally were observed. All isolates produced aerial, sparse, and cottony mycelium. However, colony pigmentation was variable among isolates CML3882, CML3885, CML3888 and CML3890, varying from dark to light pink, white, purple, wine, and reddish/blue orange. The aerial mycelium varied from white, light purple to purple (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn \u003cem\u003eF. verticillioides\u003c/em\u003e the formation of microconidia in long chains on monophialides (2.6 x 0.1 \u0026micro;m) was observed in the aerial mycelium. Branched and simple conidiophores in the aerial mycelium were also verified (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Microconidia showed an oval to elongated shape with 1.6x 0.58 \u0026micro;m. Macroconidia showed an average size of 9.5 x 1.35 \u0026micro;m. Isolates CML3886, CML3887 and LPF-FBM16 showed sparse, cottony aerial mycelium with cream to light purple coloration. Pigmentation on the back side of the colony showed cream coloration with a light brown halo in the middle.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe species \u003cem\u003eF. proliferatum\u003c/em\u003e, CML3880 (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) showed microconidia produced in short chains from polyphialides, varying from golf cue to pear-shaped format, with 1.67 x 0.57 \u0026micro;m, without septum. Macroconidia were 6\u0026ndash;8 x 3.5 \u0026micro;m, with 3\u0026ndash;5 septa. Chlamydospores were absent. Sparse aerial and cottony mycelium, with a light pink to purple color, was evidenced. Pigmentation on the back side of the colony varied from cream to light pink with a dark pink halo.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMorphological characteristics in the sexual \u003cem\u003eF. caapi\u003c/em\u003e stage, CML3881 and CML3883 (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e) showed oval to ovoid microconidia with 5\u0026ndash;15 x 2\u0026ndash;5 \u0026micro;m, with one or without septum, being predominantly septate, produced on false heads or short chains in monophialides and poliphialides measuring 17.5\u0026ndash;32.5 x 2\u0026ndash;5 \u0026micro;m. Conidiogenous cells were simple or branched conidiophores. Straight and slightly curved macroconidia, apical and basal cells slightly evident, with 3\u0026ndash;5 septa, measuring 23.5\u0026ndash;55 x 2\u0026ndash;5 \u0026micro;m, profuse production of chlamydospores in chains or clusters, terminal or intercalary, globose and cylindrical, measuring 4.5\u0026ndash;22.2 x 5-18.5 \u0026micro;m. Cottony mycelia, white to light gray pigmented. Pigmentation on the back side of the colony varied from cream to yellow.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe phylogenetic lineage denoted \u003cem\u003eFusarium\u003c/em\u003e sp.4, CML3889 and CML3892 (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e), presents whitish, flocculate-powdery aerial mycelium with cream-colored colonies. Pigmentation on the back side of the colony varied from white to cream. Microconidia are hyaline, ovoid and clavate, with 2-9x1.5-3 \u0026micro;m without septum and 7.5-13.5x2.5-5.5 \u0026micro;m with one septum, produced in false heads and short chains in simple and branched monophialides and polyphialides (17.5-32.5x2-5 \u0026micro;m). Long macroconidia, apical and basal cells slightly evident, with 3\u0026ndash;5 septa, predominantly showing 3 septa, with 21-46.5x2.0-5 \u0026micro;m. Chlamydospores in chains were observed, with smooth walls, terminal or intercalated, globose, cylindrical to sub-cylindrical, measuring 4.5-22.2x5-18.5 \u0026micro;m.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe isolate LPF-FBM15, identified as \u003cem\u003eFusarium\u003c/em\u003e sp. (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e), showed oval, clavate and ovoid microconidia, measuring 1.4\u0026ndash;3.5 x 1.2\u0026ndash;1.8 \u0026micro;m, without or with 1 septum, produced in false heads and short chains, in simple and branched monophialides with 5.5\u0026ndash;9.4 x 4 \u0026micro;m in length and polyphialides with in 4.4 x 0.880 \u0026micro;m length. Short and cup-shaped philalides were observed, measuring 3.2 x 1.08 \u0026micro;m. Chlamydospores were not observed. Macroconidia showed 2\u0026ndash;3 septa, predominantly with 3 septa; 2-septate macroconidia measuring 4.9\u0026ndash;9.5 x 1.9\u0026ndash;2.3 \u0026micro;m and 3-septate measuring 5.5\u0026ndash;12.6 x 2-2.7 \u0026micro;m. Aerial mycelium disperses and floccose with white to cream color. Pigmentation on the back side of the colony is light pink.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe isolate LPF-FBM17, identified as \u003cem\u003eFusarium\u003c/em\u003e sp. (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e), produced hyaline microconidia, clavate to ovoid, measuring 1.13\u0026ndash;1.3 x 0.59 \u0026micro;m, without or with 1 septum, predominantly without septum, produced in false heads in short chains from simple and branched monophialides or polyphialides (1.4\u0026ndash;2.5 x 0.33\u0026ndash;0.37 \u0026micro;m). Microconidia aggregated in false heads on short phialides. Macroconidia measuring 5.8 x 1.15 \u0026micro;m. Chlamydospores were observed intercalary. Aerial mycelium sparse and cottony, with white to light pink pigmentation. Pigmentation on the back side of the colony varied from cream to light pink with a pink halo in the center.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003ePathogenicity test\u003c/b\u003e\u003c/p\u003e\u003cp\u003eSymptoms started approximately two weeks after soil inoculation. Symptomatology varied between cultivars studied, in a general way resulting in yellowing of the lower leaves in the plant, foliar necrosis and darkening of plant vessels, collar and stalk rot, and death of tillers, but not of the whole plant.\u003c/p\u003e\u003cp\u003eThe species \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e, the new \u003cem\u003eFusarium\u003c/em\u003e sp.4 lineage, \u003cem\u003eFusarium\u003c/em\u003e sp. (FBM15), \u003cem\u003eFusarium\u003c/em\u003e sp. (FBM17) and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eoxysporum\u003c/em\u003e, induced symptoms in plants from cultivars Marandu and Xara\u0026eacute;s. Symptoms initiated with yellowing of the lower leaves of the plant progressing to sheath and leaf necrosis. Leaf yellowing started from the apex towards the edges, forming an inverted V shape. In time, the yellowing reached the sheath and leaf base, leading to total leaf drying. Younger leaves showed yellowing advancing to drying of the tillers. In the clump base, stalks, collars and rhizomes showed symptoms of rot.\u003c/p\u003e\u003cp\u003eThrough a longitudinal cut in the stalk, the discoloration of plant vascular tissues was verified (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). Isolates from the complex \u003cem\u003efujikuroi\u003c/em\u003e (FFSC) caused stronger rot in the stalks, collars and rhizomes of marandu grass, the isolates from the species \u003cem\u003eF. caapi\u003c/em\u003e (CML 3881 and 3883) and isolate FBM17, showed higher incidence when inoculated on cultivar Marandu (83.33%), while in cultivar Xara\u0026eacute;s isolates CML 3880 and 3883 showed an incidence of 83.33%. The new lineage \u003cem\u003eFusarium\u003c/em\u003e sp.4 (CML3889 and 3892), had higher incidence in cv. Marandu (66.66%). Isolate CML 3887, representing the species \u003cem\u003eF. verticillioides\u003c/em\u003e, showed incidence of 66.66% in both evaluated cultivars, similar to the new lineage \u003cem\u003eFusarium\u003c/em\u003e sp.4 (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), according to the incidence percentage equation used in the evaluation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eIncidence of fusariosis in Marandu and Xara\u0026eacute;s cultivars 42 days after inoculation.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eIsolates\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eIncidence (%)\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMarandu\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eXara\u0026eacute;s\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3880\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e83.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3881\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e83.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3882\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3883\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e83.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e83.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3885\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3888\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3886\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3887\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3890\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e33.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3889\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCML3892\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFBM15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFBM16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e33.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFBM17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e83.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003e\u003csup\u003e1\u003c/sup\u003eResults from two experiments were similar and were combined. Values in the table are the means of 10 replicate pots.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThus, cv. Marandu and cv. Xara\u0026eacute;s showed symptoms of the disease in tillers inoculated with \u003cem\u003eFusarium\u003c/em\u003e spp. However, the symptoms described above were also observed in cv. Xara\u0026eacute;s (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). The symptoms were more evident in rhizomes than in roots, with slight darkening of the root system being observed. We did not verify a characteristic symptom for a determined \u003cem\u003eFusarium\u003c/em\u003e sp. species. From these infected tissues, the isolates were re-isolated and showed the same morphologic characteristics as the inoculated fungi, thus fulfilling Koch\u0026rsquo;s postulates (Amorim et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Control plants showed no symptoms of the disease.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe phylogenetic analysis of the \u003cem\u003eEF-1α\u003c/em\u003e gene allowed for the identification of three already known and one new species belonging to the \u003cem\u003eFusarium fujikuroi\u003c/em\u003e species complex (FFSC). Although, some isolates were identified morphologically as being similar to \u003cem\u003eF. oxysporum\u003c/em\u003e (FOSC) and the species complex \u003cem\u003eF. incarnatum\u003c/em\u003e-\u003cem\u003eequiseti\u003c/em\u003e (FIESC). Additionally, two isolates were identified solely through morphological characteristics, exhibiting the morphotype of \u003cem\u003eF. proliferatum\u003c/em\u003e. In the present study, we verified \u003cem\u003eUrochloa\u003c/em\u003e hosts a variety of \u003cem\u003eFusarium\u003c/em\u003e species. A constant presence of species belonging to the FFCS complex in cv. Marandu and the affinity of this complex for grasses were verified.\u003c/p\u003e\u003cp\u003eThe species complex \u003cem\u003eF. fujikuroi\u003c/em\u003e was predominant among the isolates obtained from \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu showing symptoms of fusariosis. \u003cem\u003eFusarium proliferatum\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e, a new lineage designated as \u003cem\u003eFusarium\u003c/em\u003e sp.4 and two isolates here nominated as \u003cem\u003eFusarium\u003c/em\u003e sp., were identified. The new \u003cem\u003eFusarium\u003c/em\u003e sp.4 lineage is here called \u003cem\u003eF\u003c/em\u003e. \u0026ldquo;\u003cem\u003eburitiense\u003c/em\u003e\u0026rdquo;. All these isolates were obtained from the municipality of Buritizeiro, North of Minas Gerais state, Brazil (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Burgess and Summerell (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1992\u003c/span\u003e) verified diverse \u003cem\u003eFusarium\u003c/em\u003e species in native grass areas in Australia. In Kenya, different \u003cem\u003eFusarium\u003c/em\u003e species were identified as endophytes associated with forages from the genus \u003cem\u003eUrochloa\u003c/em\u003e (Kago et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eBased on phylogenetic analysis of the \u003cem\u003eEF-1α\u003c/em\u003e gene region, using the Maximum Parsimony method, two isolates were identified as \u003cem\u003eF. caapi.\u003c/em\u003e This new species is closely related to \u003cem\u003eF. mundagurra\u003c/em\u003e, belongs to the African clade, according to the theory proposed in the phylogeographic evidence of FFSC species (O\u0026rsquo;Donnell et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). In short, the genus \u003cem\u003eUrochloa\u003c/em\u003e has its center of origin in the African continent.\u003c/p\u003e\u003cp\u003eThere is difficulty in discriminating the new phylogenetic lineage \u003cem\u003eFusarium\u003c/em\u003e sp. from \u003cem\u003eF\u003c/em\u003e. \u003cem\u003emundagurra\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e based only on their morphological characterization, once all species produce conidia in short chains on phialides. Isolates of \u003cem\u003eFusarium\u003c/em\u003e sp.4 (CML3889 and CML3892), produced clavate conidia, being the most usual format when compared to oval and ovoid conidia. These two last conidia formats were commonly observed in isolates of the species \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e (CML3881 and CML3883) and species \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ebrachiariae\u003c/em\u003e and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003emundagurra\u003c/em\u003e, described in studies by Laurence et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) and Costa et al. (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Production of chlamydospores was observed in isolates of \u003cem\u003eFusarium\u003c/em\u003e sp.4, as also described in \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, discriminating them from \u003cem\u003eF. proliferatum\u003c/em\u003e in which chlamydospores are absent.\u003c/p\u003e\u003cp\u003eIsolates CML3881 and CML3883, clustered to the clade of the species \u003cem\u003eF. caapi\u003c/em\u003e. This species was reported for the first time in \u003cem\u003eU. brizantha\u003c/em\u003e seeds from different regions in Brazil, belonging to the African clade and constituting a brother group of \u003cem\u003eF\u003c/em\u003e. \u003cem\u003emundagurra\u003c/em\u003e (Costa et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Morphological characteristics of \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e are also observed in \u003cem\u003eF\u003c/em\u003e. \u003cem\u003efujikuroi\u003c/em\u003e, \u003cem\u003eF. lactis\u003c/em\u003e and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ephyllophilum\u003c/em\u003e, once all produce microconidia in short chains on polyphialides (Nirenberg et al. 1998; Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Yet, phylogenetic analysis can discriminate this species from each other. The isolate CML3880 clustered to the clade of \u003cem\u003eF. proliferatum\u003c/em\u003e, constituting an internal group with \u003cem\u003eF. fujikuroi.\u003c/em\u003e\u003c/p\u003e\u003cp\u003eA morphologic marker of \u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e is the production of microconidia in long chains on monophialides (Klittich et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Marasas et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). This characteristic was observed in isolates CML3886, CML3887 and FBM16. Nevertheless, only the first two isolates were sequenced and phylogenetically analyzed. \u003cem\u003eF\u003c/em\u003e. \u003cem\u003everticillioides\u003c/em\u003e has a wide world distribution, has a close association with maize and can cause stalk and ear rot (Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eBased on morphological characteristics, we believe that isolates FBM15 and FBM17 \u003cem\u003e(Fusarium\u003c/em\u003e sp.) belong to the FFSC, due to the production of conidia in short chains on mono and polyphyalides. These are characteristics observed in \u003cem\u003eF\u003c/em\u003e. mundagurra, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ecaapi\u003c/em\u003e, \u003cem\u003eF\u003c/em\u003e. \u003cem\u003ebrachiariae\u003c/em\u003e and \u003cem\u003eF\u003c/em\u003e. \u003cem\u003enygamai\u003c/em\u003e (Burgess and Trimboli \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1986\u003c/span\u003e; Laurence et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Costa et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Morphological markers of \u003cem\u003eF. oxysporum\u003c/em\u003e were observed in isolates FBM3, FBM6, FBM7 and FBM10. The species complex FOSC is characterized by the production of microconidia aggregated in false heads on short phialides (Gerlach and Nirenberg \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1982\u003c/span\u003e; Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn the present study, inoculation tests revealed that isolates caused typical rotting symptoms of FFSC in cultivars Marandu and Xara\u0026eacute;s. Initial symptoms were yellowing of leaves and sheath, with the latter dry and death of some tillers, symptoms observed in species of \u003cem\u003eFusarium\u003c/em\u003e sp. infecting some grass species and chickpea (Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Singh et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). The species \u003cem\u003eF\u003c/em\u003e. \u003cem\u003eproliferatum\u003c/em\u003e was already reported as pathogenic in sugarcane, producing symptoms of stalk rot in maize, sorghum and pearl millet, and producing mycotoxins in maize grains (Nordahliawate et al. 2008; Zhang et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Costa et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In the present study, the species \u003cem\u003eF. oxysporum\u003c/em\u003e produced disease symptoms in some tillers of both \u003cem\u003eU. brizantha\u003c/em\u003e cultivars, although this species has already been isolated as endophytic in \u003cem\u003eUrochloa\u003c/em\u003e seeds from various countries such as Kenya, Ethiopia and Burundi (Teasdale et al. 2019). In Central and South America and countries where banana and leguminous plants such as chickpeas are cultivated, the \u003cem\u003eF. oxysporum\u003c/em\u003e complex has caused pronounced economic losses (Ploetz \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Singh et al \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Ploetz \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eZ\u0026uacute;\u0026ntilde;iga Pereira et al. (1998) studied four species belonging to the genus \u003cem\u003eUrochloa\u003c/em\u003e, including the cv. Marandu identified fungi of the genus \u003cem\u003eFusarium\u003c/em\u003e causing symptoms in \u003cem\u003eU. brizantha\u003c/em\u003e cv. Marandu under field capacity conditions, as well as plant death 24 days after inoculation of \u003cem\u003eFusarium\u003c/em\u003e isolates. Marchi et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) studied the pathosystem \u003cem\u003eFusarium\u003c/em\u003e sp. x \u003cem\u003eUrochloa brizantha\u003c/em\u003e and \u003cem\u003ePanicun maximum\u003c/em\u003e, verifying mild symptoms with yellowing leaves, while in cv. Massai the symptoms were stronger, followed by plant dryness and death.\u003c/p\u003e\u003cp\u003eSpores or mycelium of the genus \u003cem\u003eFusarium\u003c/em\u003e may infect plant roots, directly through intact tissues or through root wounds or in secondary roots under development, causing the host disease or death (Leslie and Summerell \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Singh et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). After a longitudinal incision on the plant stalk, vascular discoloration, necrosis of internal tissues and tissue rot, were observed. As plants grow older, in addition to the yellowing leaves and sheath, stalk, collar, and rhizome rot develop. A signal of the fungus potential to systemically colonize the forage. Species of the FFSC show a high capacity to infect forages of the genus \u003cem\u003eUrochloa\u003c/em\u003e, this may become a problem for the introduction and establishment of some grass species in areas with previous reports of the disease.\u003c/p\u003e\u003cp\u003eWe identified for the first time pathogenic species of \u003cem\u003eFusarium\u003c/em\u003e to \u003cem\u003eUrochloa brizantha\u003c/em\u003e cv. Marandu also reported a new strain of \u003cem\u003eFusarium\u003c/em\u003e sp.4 in Marandu grass in Brazil. \u003cem\u003eUrochloa brizantha\u003c/em\u003e cv. Marandu may act as a source of inoculum for species within FFSC and FOSC, predominantly species from the \u003cem\u003eF\u003c/em\u003e. \u003cem\u003efujikuroi\u003c/em\u003e complex. The species \u003cem\u003eF. caapi\u003c/em\u003e, \u003cem\u003eF. verticillioides\u003c/em\u003e, \u003cem\u003eFusarium\u003c/em\u003e sp.4, \u003cem\u003eF. oxysporum\u003c/em\u003e, \u003cem\u003eF. proliferatum\u003c/em\u003e, and the isolates FBM17 and FBM15 (\u003cem\u003eFusarium\u003c/em\u003e sp.) were pathogenic and aggressive to both cvs. Marandu and Xara\u0026eacute;s. Morphological markers cannot be the only tool for distinguishing species of \u003cem\u003eF\u003c/em\u003e. \u003cem\u003efujikuroi\u003c/em\u003e complex.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe first author wishes to thank CAPES (Coordena\u0026ccedil;\u0026atilde;o de Aperfei\u0026ccedil;oamento de Pessoal de N\u0026iacute;vel Superior) for the scholarship and FAPEMIG (Funda\u0026ccedil;\u0026atilde;o de Amparo \u0026agrave; Pesquisa do Estado de Minas Gerais), APQ-00472-22, for financial support. The authors would also like to thank the Universidade Federal de Minas Gerais for its technical support and infrastructure, as well as the Plant Pathology team (GEFIT-UFMG). \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization: FSR and FLA; Methodology: FSR, FLA, and MFGF; Formal analysis and invetigation: FLA, MFGF, MMC; Writing-original draft preparation; FLA and FSR; Writing-review, and editing: GLDL, JMAR and LHP; Funding acquisition: FSR and LHP; Resources: FLA, MMC, LHP and FSR; Supervision: FSR.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data analyzed in this research is available from the corresponding author upon reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics declaration \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAmorim L, Rezende JAR, Bergamin Filho A (Eds.) 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Fungal Divers., 46:1-27 doi.org/10.1007/s13225-010-0075-8\u003c/li\u003e\n\u003cli\u003eSteenkamp ET, Rodas CA, Kvas M, Wingfield MJ (2012) \u003cem\u003eFusarium circinatum\u003c/em\u003e and pitch canker of \u003cem\u003ePinus\u003c/em\u003e in Colombia. Australasian Plant Pathology 41:483-491 doi.org/10.1007/s13313-012-0120-z\u003c/li\u003e\n\u003cli\u003eTamura K, Stecher G, Kumar S (2021) MEGA11: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods. Molecular Biology and Evolution. 38:3022-3027 doi.org/10.1093/molbev/msab120\u003c/li\u003e\n\u003cli\u003eTeasdale SE, Caradus JR, Johnson LJ (2018) Fungal endophyte diversity from tropical forage grass \u003cem\u003eBrachiaria\u003c/em\u003e. Plant Ecology \u0026amp; Diversity. 11:611-624 doi.org/10.1080/17550874.2019.1610913\u003c/li\u003e\n\u003cli\u003eTompson JD, Higgins DG, Gibson TJ (1994) CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Research. 22:4673-4680 doi.org/10.1093/nar/22.22.4673\u003c/li\u003e\n\u003cli\u003eWingfield MJ, Hammerbacher A, Ganley RJ, Steenkamp ET, Gordon TR, Wingfield BD, Coutinho TA (2008) Pitch canker caused by \u003cem\u003eFusarium circinatum\u003c/em\u003e: a growing threat to pine plantations and forests worldwide. Australasian Plant Pathology 37:319-334 doi.org/10.1071/ap08036\u003c/li\u003e\n\u003cli\u003eZhang L, Wang J, Zhang C, Wang Q (2012) Analysis of potential fumonisin-producing \u003cem\u003eFusarium\u003c/em\u003e species in corn products from three main maize-producing \u0026aacute;reas in eastern China. Journal of the Science of Food and Agriculture 93:693-701 doi.org/10.1002/jsfa.5794\u003c/li\u003e\n\u003cli\u003eZ\u0026uacute;\u0026ntilde;iga PC, Gonz\u0026aacute;lez QR, Bustamante E, Argel P (1998) Influencia de la humedad del suelo sobre la susceptibilidad de \u003cem\u003eBrachiaria \u003c/em\u003ea hongos pat\u0026oacute;genos. Manejo Integrado de Plagas 49:51-57. Available at: https://repositorio.catie.ac.cr/handle/11554/7447?show=full (last checked 25 Jul 2023)\u003c/li\u003e\n\u003c/ol\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":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"tropical-plant-pathology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"tppa","sideBox":"Learn more about [Tropical Plant Pathology](https://www.springer.com/journal/40858)","snPcode":"40858","submissionUrl":"https://www.editorialmanager.com/tppa","title":"Tropical Plant Pathology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Fusarium fujikuroi species complex, fusariosis, marandu grass, molecular phylogeny, sudden death syndrome","lastPublishedDoi":"10.21203/rs.3.rs-7188016/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7188016/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn Brazil, the sudden death disease of Marandu grass (\u003cem\u003eUrochloa brizantha\u003c/em\u003e cv. Marandu) has caused grassland degradation. In the north of Minas Gerais state, a disease has been reported in pastures with similar symptoms to the sudden death of grasses. Thus, the objectives of this study were (i.) to identify \u003cem\u003eFusarium\u003c/em\u003e species associated with the sudden death disease of Marandu grass using molecular phylogeny and morphological markers and (ii.) to test the pathogenicity of \u003cem\u003eFusarium\u003c/em\u003e isolates on Marandu and Xara\u0026eacute;s cultivars. All isolates used in this work were obtained from typical cultures of the genus \u003cem\u003eFusarium\u003c/em\u003e, grown from isolated tissues of Marandu grass with symptoms of the disease, collected in the North region of Minas Gerais, Brazil. Twelve phylogenetic species were identified among the 17 isolates based on comparing partial sequences of the elongation factor 1-α gene (TEF-1-α). These species belong to the \u003cem\u003eF. fujikuroi\u003c/em\u003e (FFSC, n\u0026thinsp;=\u0026thinsp;10) and \u003cem\u003eF. oxysporum\u003c/em\u003e (FOSC, n\u0026thinsp;=\u0026thinsp;5) species complexes. In the pathogenicity test, the isolates induced symptoms of leaf yellowing, shoot drying, and stem rot in the cultivars Marandu and Xara\u0026eacute;s, especially the isolates belonging to the FFSC. The \u003cem\u003eFusarium\u003c/em\u003e sp. 4 strain will be described and elevated to the species level, representing a new phylogenetic species in the FFSC. Our study has shown that several species of \u003cem\u003eFusarium\u003c/em\u003e cause pathogenicity to Marandu and Xara\u0026eacute;s grasses, which can serve as an inoculum source for crops of great agricultural significance. However, this pathosystem can also harbor new species of \u003cem\u003eFusarium\u003c/em\u003e. In our work, we demonstrated for the first time the pathogenicity of \u003cem\u003eFusarium\u003c/em\u003e species in the cultivars Marandu and Xara\u0026eacute;s.\u003c/p\u003e","manuscriptTitle":"Fusarium species pathogenic to Urochloa brizantha in the north de Minas Gerais, Brazil","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-05 16:45:26","doi":"10.21203/rs.3.rs-7188016/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revisions","date":"2025-09-04T08:10:25+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-08-03T12:31:45+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-31T20:11:00+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Tropical Plant Pathology","date":"2025-07-31T19:17:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-31T14:56:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"Tropical Plant Pathology","date":"2025-07-25T07:57:35+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"tropical-plant-pathology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"tppa","sideBox":"Learn more about [Tropical Plant Pathology](https://www.springer.com/journal/40858)","snPcode":"40858","submissionUrl":"https://www.editorialmanager.com/tppa","title":"Tropical Plant Pathology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"62ea50d0-1eca-433e-8f98-d0c32ee8a629","owner":[],"postedDate":"August 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-02-23T12:59:03+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-05 16:45:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7188016","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7188016","identity":"rs-7188016","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}