First Report of Rhizoctonia solani AG 2-2IIIB causing Damping-off on Bottle Gourd (Lagenaria siceraria) Seedlings in Bangladesh

First Report of Rhizoctonia solani AG 2-2IIIB causing Damping-off on Bottle Gourd (Lagenaria siceraria) Seedlings in Bangladesh | 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 First Report of Rhizoctonia solani AG 2-2IIIB causing Damping-off on Bottle Gourd (Lagenaria siceraria) Seedlings in Bangladesh Md Ziaur Rahman Bhuiyan, Mahmuda Akter, Nazneen Sultana, Md. Jahidul Islam, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8263008/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Bottle gourd is a popular winter vegetable crop in Bangladesh. Bottle gourd seedlings with damping off symptoms were collected in October 2024 from Savar upazila, Dhaka. The causal agent was grown in growth media, and studied the morphological features. Molecular identity was confirmed through amplification of internal-transcribed spacer (ITS) region, RNA polymerase II ( rpb2 ), and β-tubulin ( tub2 ) genes. Based on morphological and molecular investigations, the pathogen was verified as Rhizoctonia solani AG 2–2 IIIB. Pathogenicity test was done to fulfill the Koch’s postulates. These findings will be useful to design an effective disease management program of cucurbits in Bangladesh. Fungus soil borne seedling diseases bottle gourd ITS rpb2 tub2 Figures Figure 1 Figure 2 Full Text Bottle gourd ( Lagenaria siceraria (Mol.) Stand. is originated from Africa, which then widely distributed, and now cultivated in many countries including China, Europe, Haiti, Hawaii, India, Iraq, Turkey, Venezuela, and Bangladesh (Kistler et al. 2014; Richardson 1972). Bottle gourd is an economically important vegetable crop in Bangladesh under Cucurbitaceae family, and a leading source of nutrition in human diet (Rahaman 2003). Bottle gourd is a year round vegetable crop, cultivated in Mymenshing, Manikganj, Rajshahi, Norshingdi, Savar, Jamalpur, Rangpur, and Comilla districts in Bangladesh. Seedlings of bottle gourd can be affected by several diseases such as damping off, wilting, seedling rot etc. in the nursery, greenhouse and in the field conditions (Zitter et al. 1996). In Bangladesh, powdery mildew, virus mosaic disease, gummy stem blight, anthracnose, fruit rot, downy mildew and wilting are the major bottle gourd diseases. Various pathogens including Colletotrichum, Alternaria, Pythium, Botrytis, Cercospora, Pseudoperonospora, Plectosporium, Sphaerotheca, Cladosporium, Septoria, Verticillium causes significant crop losses in cucurbits worldwide (Sean et al. 2021; Aktaruzzaman et al. 2019). Rhizoctonia solani is a common seed-and soil-borne necrotrophic fungus which causes various diseases to cultivated fields, ornamental plants, and turf grass. R. solani is prevalent in both tropical and temperate region of the world (Salazar et al. 2000). R. solani represents remarkable genetic variations and comprises 13-different anastomosis groups (AGs), which are genetically distinctive populations (Ogoshi, 1996; Sharon et al., 2006). This fungus primarily exists as mycelia in nature and also survives for a long time in the soil through resting spore called sclerotia and forms sexual spores every so often (Cubeta and Vilgalys, 1997). Typical damping-off seedling symptom includes a watery rot on the hypocotyl at or near the soil line, light to dark brown lesion. Germinating seed can also be attacked by these fungi before they emerge from the soil (pre-emerging damping off), resulting in poor stands (Paulitz et al. 2006). In Mid-September 2024, bottle gourd seedlings with dark brown to black discolored were observed from a grower’s seed bed. Diseased plants showed damping off symptoms including water soaked lesions in the affected regions with limited feeder roots and rootlets. Affected seedling showed 25 to 30 % disease severity. A severe decline of gourd seedlings were collected and brought to Plant Pathology Laboratory, Sher-e-Bangla Agricultural University, Dhaka. Rhizoctonia solani was consistently isolated from the damping off seedlings of bottle gourd. The aim of this study was to identify and characterize the causal agent of the host disease. Twenty five bottle gourd seedlings were collected from a grower’s commercial nursery located at Savar Upazila under Dhaka District in Mid-October 2024, which had dark brown to black discolored lesions with typical damping-off symptoms (Fig. 1A & 1B). Symptomatic seedlings had approximately 30 to 40% disease severity. Samples were surfaced sterilized and plated on to the potato dextrose agar (PDA) media at 25 ° C in dark condition for 3 days. Growing hyphal tips were transferred to PDA and clarified V8 (CV8) agar media to observe the pure culture and development of sclerotia. Morphological features were studied under compound microscope and inverted florescent compound microscope at 40X magnification (VWR ® ELWD N.A. 0.30). Identification of R . solani was done by comparison with morphological characteristics, visual observation, and microscopic study. R. solani isolates were grown in the PDA media amended with streptomycin sulphate at 200 mg/L for 10 days at room temperature. Genomic DNA was extracted from the pure culture of all isolate using DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocol and stored at -20°C for further use. Molecular identification was done by amplification and sequencing of the internal transcribed spacer (ITS, ITS1/ITS4) regions and largest RNA polymerase II subunit ( rpb2 ) (O'Donnell et al. 2010), and β-tubulin ( tub2 ) (Glass and Donaldson 1995) genes (Table 1). The PCR reaction was carried out in a 25-µL reaction mixture containing 1.0 µL of each primer (10 µmol/ml), 2.0 µL of genomic DNA (10 ng/µL), 12.5 µL of 2X PCR MasterMix (Promega ® GoTaq Green) and 8.5 µL of nuclease free water. The PCR conditions used were as follows: (i) ITS primers: initial denaturation was performed at 95°C for 10 minutes, followed by 30 cycles in series of 95°C for 1 min, 57°C for 1 min, and 72°C for 90 s, with a final cycle at 72°C for 10 minutes, (ii) rpb2 primers: 1 cycle of 90 s at 94°C, followed by 40 cycles of 30 s at 94°C, 90 s at 55°C, and 2 min at 68°C, followed final extension for 5 min at 68°C, and for tub2 primers: 94°C for 1 min; 58 or 68°C for 1 min; 72°C for 1 min; repeat protocol for 32 cycles, with a 5- to 10-s extension time per cycle. The PCR products were run on 1.5% gel stained with SYBER Safe DNA gel stain in 10X TAE buffer to visualize under the UV light. PCR products were cleaned with Exo SAP-IT (Thermo Fisher Scientific) and sent for sequencing at Genecreate Biotech, China. Bottle gourd seeds were grown into 12 × 10 cm plastic bags containing autoclaved soil at the Sher-e-Bangla Agricultural University, Dhaka-1207 in the greenhouse condition. To fulfill the Koch’s postulates, pathogenicity assay of the isolates was conducted on ten bottle gourd (cv. BARI LAU 3) at planting. Seeds were surface sterilized with 70% ethanol before sowing in the plastic bag. The experiment was conducted twice with a completely randomized design (CRD) with four replications and four seeds per replicate each time. Mycelial discs (5 mm) of ten-day old culture of R. solani were inoculated to individual seeds at 2.5 cm soil depth for 5 days at 22±2°C with high relative humidity (>90%) in a 14/10-h photoperiod (600-W high-pressure sodium lamps) in the misting chamber and they were kept constantly wet by placing them in trays (40×20×8 cm) filled with 2 to 3 cm of water. The mock inoculation to seeds was done with agar plug without R. solani mycelia. After 5-days, pots were transferred to the greenhouse at 25°C at 14 h photoperiod and evaluated the pathogenicity at 10 days post inoculation. Five R. solani isolates were obtained from the symptomatic bottle gourd seedlings. All isolates were morphologically identical and produced brown to dark brown, fluffy (Fig. 1C & 1D). Hyphae were septate, initially hyaline and become grey to brown at maturity. Hyphae were branched at right angles with a constriction at the base (Fig. 1E). Sclerotia were variable size, dark-brown to tan colored (Fig. 1F), abundant, sparsely distributed to the growth media (Fig. 1C & 1D). The fungus did not produce any conidia and conidiophore. The causal agent was identified as Rhizoctonia solani AG 2-2 IIIB (Sneh et al. 1991). The BLASTn of the consensus nucleotide sequences of all isolates for respective loci were identical. Nucleotide sequences of all isolates were submitted to the NCBI GenBank with accessions ITS (PV101462, PV101463), rpb2 (PV360730, PV360731), and tub2 (PX548722; PX548723) which were 100% similar to the reference sequences for ITS (FJ492123, KR736348), rbp2 (OP832150, OP832157), and tub2 (FJ392720) of R. solani AG 2-2 IIIB. Ten day post inoculation, inoculated seeds developed post emergence damping off symptoms which includes brown to black discolored hypocotyl of the emerged seedlings, rot decay, and death of seedlings (Fig. 1A & 1B). Seedlings that emerged from mock inoculated seeds were asymptomatic (Fig. 2C). R. solani isolates were consistently re-isolated from the inoculated seedling and morphology of the isolates retrieved from the inoculated plants was identical to the field isolates of R. solani . Rhizoctonia solani is a destructive plant pathogen to agronomic, horticultural, and forest plants which causes significant yield losses annually. In this study, we have investigated and characterized the causal agent of bottle seedling damping off. To our knowledge, this is the first report of Rhizoctonia solani AG 2-2IIIB causing damping-off on bottle gourd ( Lagenaria siceraria ) seedlings in Bangladesh. R. solani considered to be a serious threat to economic production of cucurbits worldwide. Effective management of R. solani disease in cucurbits integrates combination of cultural, biological, and chemical methods. Favorable temperature for damping-off in cucurbits and other crops under wet and warm conditions at 20 to 30°C (68 to 86°F) (Minier and Hanson 2021). Damping off seedling results in poor stand establishment, which can occur as a pre-emergence or seed decay (Baker 1970). Fields without a history of R. solani diseases should be selected for planting and crop rotation with non-host for at least three years (Buhre et al. 2009). Extra care should be taken if planting done at early to ensure soil temperatures are adequately warm. Poorly drained bed or areas and excessive irrigation to be avoided which increase the disease incidence. Currently, there are no commercial cucurbit varieties with resistant to R. solani damping off seedlings in Bangladesh. Therefore, fungicide application is needed for effective disease management of this pathogen. Azoxystrobin, pyraclostrobin (QoIs) and Penthiopyrad, sedaxane, and fluxapyroxad (SDHI) class of fungicides are considered to be most effective in controlling R. solani (Balba 2007; Avenot and Michailides 2010; Liu and Khan 2016a; Bartlett et al. 2002). Seed treatment with effective fungicides such as fludioxonil (FRAC 12), Thiram (FRAC M3), tebuconazole (FRAC 3) + trifloxystrobin (FRAC 11), and propiconazole (FRAC 3) are recommended for damping off disease management (Campion et al. 2003; Sharma et al. 2021). Foliar or in-furrow application of Azoxystrobin and pyraclostrobin (FRAC 11) is very effective for management of R. solani . However, repeated use of single site mode of action of fungicides leads the development of resistance in pathogens populations. It has been reported that the QoI and SDHI fungicides have high and medium to high risk of developing resistance (FRAC 2024). Biological control of R. solani spp. with antagonistic bacteria, Bacillus spp. Burkholderia and Pseudmonas sp. and some fungal species such as Trichoderma harzianum , and T. hamatum have shown excellent efficacy (Verdoodt, 2023; Anitha and Das 2011; Aydin 2022; Farhaoui et al. 2023). This pathogen has wide host ranges and distributed in both the temperate and tropical climatic conditions and capable causing disease in many economically important crops including cereals, vegetables, ornamental and horticultural crops (Salazar et al. 2000). R. solani AG 2-2 has been reported to be destructive to many crops includes dry bean, soybeans, corn etc. (Sneh et al. 1991; Englkes and Windels 1996; Harveson 2009). In the recent past, it has been reported that the bottle gourd seedlings at emergence has increased in location including Manikganj, Tangail, Netrokona, Jamalpur, Rangpur, Niphamari, Savar, and Norshingdi areas. Identification of the seedling damping off disease in cucurbits was confirmed only based on host symptoms. We have studied the morphological features of the Rhizoctonia solani AG 2-2IIIB followed by microscopy, pathogenicity and molecular characterization through multilocus sequence typing. To our knowledge, this is the first report of R. solani AG-2-2 IIIB causes seedling damping off bottle gourd in Bangladesh. This finding will be useful to design an effective disease management program to ensure economic production of cucurbits in Bangladesh. Declarations Acknowledgements The authors would like to thanks Sher-e-Bangla Agricultural University Research System (SAURES) and Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh. Author contributions Dr. Md Ziaur Rahman Bhuiyan : Conceptualization, investigation, supervision, resources and writing – original draft. Mahmuda Akter : Writing – review & editing. Dr. Nazneen Sultana : Writing–review & editing. Md. Jahidul Islam : Writing – review & editing. Md. Akash Miah : Isolation, microscopy, and identification of the pathogen, and Md. Ferdous Alom : Isolation, microscopy, and identification of the pathogen. Conflict of interest The authors declare that they have no conflict of interest. Ethical approval This article does not contain any studies with human participants or animals performed by any of the authors. 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Pp 315-322 Zitter TA, Hopkins DL, Thomas CE (1996) Compendium of Cucurbit Diseases. American Phytopathological Society Press, St. Paul, MN. Table Table 1. Primers were used in this study. Locus Primer Primer Sequence ( 5'-3') Reference ITS ITS1 5'-TCCGTAGGTGAACCTGCGG-3' White et al. 1990 ITS4 5'-TCCTCCGCTTATTGATATGC-3' rpb2 5F2 5'- GGGGWGAYCAGAAGAAGGC-3' O'Donnell et al. 2010 7cR 5'- CCCATRGCTTGYTTRCCCAT-3' tub2 Bt2a 5'-GGTAACCAAATCGGTGCTGCTTTC-3' Glass and Donaldson 1995 Bt2b 5'-ACCCTCAGT GTAGTG ACC CTTGGC-3' Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8263008","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":558504654,"identity":"40bbe94c-9062-4662-b016-1a691359d920","order_by":0,"name":"Md Ziaur Rahman Bhuiyan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6klEQVRIiWNgGAWjYDACZjApIcfPzHwAInKAgY2Bh7AWC2PJ9rYEIrVAQEXihjNnDIjTIt/O/Ey6gkHCmOFGzucPP9sY5PhuJLA9eINHC2Mzm5nkGaBfGGfkbpPsbWMwlryRwG44B59XmBnMJBuAtjBL5G5j4G1jSNwAtEUan8PYmNm/gbQktknkPP74t42hnqAWHmYesC2JPTxnGKSBtiQYENIiwcxTbAlymAR7m5m0zDkJw5lnHrbj9Yt8//GNNxsY6uTsDzM//vimzEae73jyMbwhBgaM/xC2grgNhDSMglEwCkbBKCAAAKeWQ4AfZxTtAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-6995-3518","institution":"Sher-e-Bangla Agricultural University","correspondingAuthor":true,"prefix":"","firstName":"Md","middleName":"Ziaur Rahman","lastName":"Bhuiyan","suffix":""},{"id":558504655,"identity":"0a9117a1-78cd-43cd-8a46-063e2386571e","order_by":1,"name":"Mahmuda Akter","email":"","orcid":"","institution":"Sher-e-Bangla Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Mahmuda","middleName":"","lastName":"Akter","suffix":""},{"id":558504656,"identity":"5af8f8ea-a4cd-4451-90b1-cab698fe31dc","order_by":2,"name":"Nazneen Sultana","email":"","orcid":"","institution":"Sher-e-Bangla Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Nazneen","middleName":"","lastName":"Sultana","suffix":""},{"id":558504657,"identity":"97840614-54c3-4e0f-a7f9-0b00b503982a","order_by":3,"name":"Md. 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13:47:55","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":64032,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8263008/v1/b6eea0ce42d20f6973245e50.html"},{"id":98319120,"identity":"24aa3c48-a55c-4a82-b11d-92b0574514da","added_by":"auto","created_at":"2025-12-16 13:47:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":385631,"visible":true,"origin":"","legend":"\u003cp\u003e(A-B) Bottle gourd seedlings had dark brown to black water soaked lesions (blue arrows) were collected from the nursery, (C-D) pure colonies of \u003cem\u003eR. solani\u003c/em\u003e grown in the PDA and CV8 media had brown to blackish mycelial mass and abundant sclerotia, (E) septate mycelia, branched at right angles with a constriction at the base showing 90\u003csup\u003e0\u003c/sup\u003e angle to parental hyphae (scale bar=100µm), (F) sclerotia were dark brown to tan colored (scale bar=100µm).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8263008/v1/706119e36d76600f75cc0c7b.png"},{"id":98319119,"identity":"59115e1f-317b-4f00-b57d-8a11a337a9a3","added_by":"auto","created_at":"2025-12-16 13:47:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":435206,"visible":true,"origin":"","legend":"\u003cp\u003ePathogenicity assay; (A-B) \u003cem\u003eR. solani\u003c/em\u003e AG 2-2IIIB inoculated seedlings developed brown to black lesion on the hypocotyl, and damping off symptoms on the bottle gourd seedlings, while (C) the mock inoculated seedlings were symptomless.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8263008/v1/dbd7f5a7c136c6a3724cbcfb.png"},{"id":101397740,"identity":"5757d2e4-e764-4a02-94d7-6f6685f55520","added_by":"auto","created_at":"2026-01-29 09:36:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1416672,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8263008/v1/3fa31f39-daca-4e62-a901-cf978ed38f58.pdf"}],"financialInterests":"","formattedTitle":"First Report of Rhizoctonia solani AG 2-2IIIB causing Damping-off on Bottle Gourd (Lagenaria siceraria) Seedlings in Bangladesh","fulltext":[{"header":"Full Text","content":"\u003cp\u003eBottle gourd (\u003cem\u003eLagenaria siceraria\u003c/em\u003e (Mol.) Stand. is originated from Africa, which then widely distributed, and now cultivated in many countries including China, Europe, Haiti, Hawaii, India, Iraq, Turkey, Venezuela, and Bangladesh (Kistler et al. 2014; Richardson 1972). Bottle gourd is an economically important vegetable crop in Bangladesh under Cucurbitaceae family, and a leading source of nutrition in human diet (Rahaman 2003). Bottle gourd is a year round vegetable crop, cultivated in Mymenshing, Manikganj, Rajshahi, Norshingdi, Savar, Jamalpur, Rangpur, and Comilla districts in Bangladesh. Seedlings of bottle gourd can be affected by several diseases such as damping off, wilting, seedling rot etc. in the nursery, greenhouse and in the field conditions (Zitter et al. 1996). In Bangladesh, powdery mildew, virus mosaic disease, gummy stem blight, anthracnose, fruit rot, downy mildew and wilting are the major bottle gourd diseases. Various pathogens including \u003cem\u003eColletotrichum, Alternaria, Pythium, Botrytis, Cercospora, Pseudoperonospora, Plectosporium, Sphaerotheca, Cladosporium, Septoria, Verticillium\u003c/em\u003e causes significant crop losses in cucurbits worldwide (Sean et al. 2021; Aktaruzzaman et al. 2019).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eRhizoctonia solani\u003c/em\u003e is a common seed-and soil-borne necrotrophic fungus which causes various diseases to cultivated fields, ornamental plants, and turf grass. \u003cem\u003eR. solani\u003c/em\u003e is prevalent in both tropical and temperate region of the world (Salazar et al. 2000). \u003cem\u003eR. solani\u003c/em\u003e represents remarkable genetic variations and comprises 13-different anastomosis groups (AGs), which are genetically distinctive populations (Ogoshi, 1996; Sharon et al., 2006). This fungus primarily exists as mycelia in nature and also survives for a long time in the soil through resting spore called sclerotia and forms sexual spores every so often (Cubeta and Vilgalys, 1997). Typical damping-off seedling symptom includes a watery rot on the hypocotyl at or near the soil line, light to dark brown lesion. Germinating seed can also be attacked by these fungi before they emerge from the soil (pre-emerging damping off), resulting in poor stands (Paulitz et al. 2006).\u003c/p\u003e\n\u003cp\u003eIn Mid-September 2024, bottle gourd seedlings with dark brown to black discolored were observed from a grower’s seed bed. Diseased plants showed damping off symptoms including water soaked lesions in the affected regions with limited feeder roots and rootlets. Affected seedling showed 25 to 30 % disease severity. A severe decline of gourd seedlings were collected and brought to Plant Pathology Laboratory, Sher-e-Bangla Agricultural University, Dhaka. \u003cem\u003eRhizoctonia solani\u003c/em\u003e was consistently isolated from the damping off seedlings of bottle gourd. The aim of this study was to identify and characterize the causal agent of the host disease.\u003c/p\u003e\n\u003cp\u003eTwenty five bottle gourd seedlings were collected from a grower’s commercial nursery located at Savar Upazila under Dhaka District in Mid-October 2024, which had dark brown to black discolored lesions with typical damping-off symptoms (Fig. 1A \u0026amp; 1B). Symptomatic seedlings had approximately 30 to 40% disease severity. Samples were surfaced sterilized and plated on to the potato dextrose agar (PDA) media at 25\u003csup\u003e°\u003c/sup\u003eC in dark condition for 3 days. Growing hyphal tips were transferred to PDA and clarified V8 (CV8) agar media to observe the pure culture and development of sclerotia. Morphological features were studied under compound microscope and inverted florescent compound microscope at 40X magnification (VWR\u003csup\u003e®\u003c/sup\u003e ELWD N.A. 0.30). Identification of \u003cem\u003eR\u003c/em\u003e. \u003cem\u003esolani\u003c/em\u003e was done by comparison with morphological characteristics, visual observation, and microscopic study.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eR. solani\u003c/em\u003e isolates were grown in the PDA media amended with streptomycin sulphate at 200 mg/L for 10 days at room temperature. Genomic DNA was extracted from the pure culture of all isolate using DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocol and stored at -20°C for further use. Molecular identification was done by amplification and sequencing of the internal transcribed spacer (ITS, ITS1/ITS4) regions and largest RNA polymerase II subunit (\u003cem\u003erpb2\u003c/em\u003e) (O'Donnell et al. 2010), and β-tubulin (\u003cem\u003etub2\u003c/em\u003e) (Glass and Donaldson 1995) genes (Table 1). The PCR reaction was carried out in a 25-µL reaction mixture containing 1.0 µL of each primer (10 µmol/ml), 2.0 µL of genomic DNA (10 ng/µL), 12.5 µL of 2X PCR MasterMix (Promega\u003csup\u003e®\u003c/sup\u003e GoTaq Green) and 8.5 µL of nuclease free water. The PCR conditions used were as follows: (i) ITS primers: initial denaturation was performed at 95°C for 10 minutes, followed by 30 cycles in series of 95°C for 1 min, 57°C for 1 min, and 72°C for 90 s, with a final cycle at 72°C for 10 minutes, (ii) \u003cem\u003erpb2\u003c/em\u003e primers: 1 cycle of 90 s at 94°C, followed by 40 cycles of 30 s at 94°C, 90 s at 55°C, and 2 min at 68°C, followed final extension for 5 min at 68°C, and for \u003cem\u003etub2\u003c/em\u003e primers: 94°C for 1 min; 58 or 68°C for 1 min; 72°C for 1 min; repeat protocol for 32 cycles, with a 5- to 10-s extension time per cycle. The PCR products were run on 1.5% gel stained with SYBER Safe DNA gel stain in 10X TAE buffer to visualize under the UV light. PCR products were cleaned with Exo SAP-IT (Thermo Fisher Scientific) and sent for sequencing at Genecreate Biotech, China.\u003c/p\u003e\n\u003cp\u003eBottle gourd seeds were grown into 12 × 10 cm plastic bags containing autoclaved soil at the Sher-e-Bangla Agricultural University, Dhaka-1207 in the greenhouse condition. To fulfill the Koch’s postulates, pathogenicity assay of the isolates was conducted on ten bottle gourd (cv. BARI LAU 3) at planting. Seeds were surface sterilized with 70% ethanol before sowing in the plastic bag. The experiment was conducted twice with a completely randomized design (CRD) with four replications and four seeds per replicate each time. Mycelial discs (5 mm) of ten-day old culture of \u003cem\u003eR. solani \u003c/em\u003ewere inoculated to individual seeds at 2.5 cm soil depth for 5 days at 22±2°C with high relative humidity (\u0026gt;90%) in a 14/10-h photoperiod (600-W high-pressure sodium lamps) in the misting chamber and they were kept constantly wet by placing them in trays (40×20×8 cm) filled with 2 to 3 cm of water. The mock inoculation to seeds was done with agar plug without \u003cem\u003eR. solani \u003c/em\u003emycelia. After 5-days, pots were transferred to the greenhouse at 25°C at 14 h photoperiod and evaluated the pathogenicity at 10 days post inoculation.\u003c/p\u003e\n\u003cp\u003eFive \u003cem\u003eR. solani \u003c/em\u003eisolates were obtained from the symptomatic bottle gourd seedlings. All isolates were morphologically identical and produced brown to dark brown, fluffy (Fig. 1C \u0026amp; 1D). Hyphae were septate, initially hyaline and become grey to brown at maturity. Hyphae were branched at right angles with a constriction at the base (Fig. 1E). Sclerotia were variable size, dark-brown to tan colored (Fig. 1F), abundant, sparsely distributed to the growth media (Fig. 1C \u0026amp; 1D). The fungus did not produce any conidia and conidiophore. The causal agent was identified as \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG 2-2 IIIB (Sneh et al. 1991). The BLASTn of the consensus nucleotide sequences of all isolates for respective loci were identical. Nucleotide sequences of all isolates were submitted to the NCBI GenBank with accessions ITS (PV101462, PV101463), \u003cem\u003erpb2\u003c/em\u003e (PV360730, PV360731), and \u003cem\u003etub2\u003c/em\u003e (PX548722; PX548723) which were 100% similar to the reference sequences for ITS (FJ492123, KR736348), \u003cem\u003erbp2\u003c/em\u003e (OP832150, OP832157), and \u003cem\u003etub2\u003c/em\u003e (FJ392720) of \u003cem\u003eR. solani\u003c/em\u003e AG 2-2 IIIB. Ten day post inoculation, inoculated seeds developed post emergence damping off symptoms which includes brown to black discolored hypocotyl of the emerged seedlings, rot decay, and death of seedlings (Fig. 1A \u0026amp; 1B). Seedlings that emerged from mock inoculated seeds were asymptomatic (Fig. 2C). \u003cem\u003eR. solani\u003c/em\u003e isolates were consistently re-isolated from the inoculated seedling and morphology of the isolates retrieved from the inoculated plants was identical to the field isolates of\u003cem\u003e R. solani\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eRhizoctonia solani\u003c/em\u003e is a destructive plant pathogen to agronomic, horticultural, and forest plants which causes significant yield losses annually. In this study, we have investigated and characterized the causal agent of bottle seedling damping off. To our knowledge, this is the first report of \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG 2-2IIIB causing damping-off on bottle gourd (\u003cem\u003eLagenaria siceraria\u003c/em\u003e) seedlings in Bangladesh. \u003cem\u003eR. solani \u003c/em\u003econsidered to be a serious threat to economic production of cucurbits worldwide. Effective management of \u003cem\u003eR. solani\u003c/em\u003e disease in cucurbits integrates combination of cultural, biological, and chemical methods. Favorable temperature for damping-off in cucurbits and other crops under wet and warm conditions at 20 to 30°C (68 to 86°F) (Minier and Hanson 2021). Damping off seedling results in poor stand establishment, which can occur as a pre-emergence or seed decay (Baker 1970). Fields without a history of \u003cem\u003eR. solani\u003c/em\u003e diseases should be selected for planting and crop rotation with non-host for at least three years (Buhre et al. 2009). Extra care should be taken if planting done at early to ensure soil temperatures are adequately warm. Poorly drained bed or areas and excessive irrigation to be avoided which increase the disease incidence. Currently, there are no commercial cucurbit varieties with resistant to \u003cem\u003eR. solani\u003c/em\u003e damping off seedlings in Bangladesh. Therefore, fungicide application is needed for effective disease management of this pathogen. Azoxystrobin, pyraclostrobin (QoIs) and Penthiopyrad, sedaxane, and fluxapyroxad (SDHI) class of fungicides are considered to be most effective in controlling \u003cem\u003eR. solani\u003c/em\u003e (Balba 2007; Avenot and Michailides 2010; Liu and Khan 2016a; Bartlett et al. 2002). Seed treatment with effective fungicides such as fludioxonil (FRAC 12), Thiram (FRAC M3), tebuconazole (FRAC 3) + trifloxystrobin (FRAC 11), and propiconazole (FRAC 3) are recommended for damping off disease management (Campion et al. 2003; Sharma et al. 2021). Foliar or in-furrow application of Azoxystrobin and pyraclostrobin (FRAC 11) is very effective for management of \u003cem\u003eR. solani\u003c/em\u003e. However, repeated use of single site mode of action of fungicides leads the development of resistance in pathogens populations. It has been reported that the QoI and SDHI fungicides have high and medium to high risk of developing resistance (FRAC 2024). Biological control of \u003cem\u003eR. solani\u003c/em\u003e spp. with antagonistic bacteria, \u003cem\u003eBacillus\u003c/em\u003e spp. \u003cem\u003eBurkholderia\u003c/em\u003e and \u003cem\u003ePseudmonas\u003c/em\u003e sp. and some fungal species such as \u003cem\u003eTrichoderma harzianum\u003c/em\u003e, and \u003cem\u003eT. hamatum\u003c/em\u003e have shown excellent efficacy (Verdoodt, 2023; Anitha and Das 2011; Aydin 2022; Farhaoui et al. 2023). This pathogen has wide host ranges and distributed in both the temperate and tropical climatic conditions and capable causing disease in many economically important crops including cereals, vegetables, ornamental and horticultural crops (Salazar et al. 2000). \u003cem\u003eR. solani\u003c/em\u003e AG 2-2 has been reported to be destructive to many crops includes dry bean, soybeans, corn etc. (Sneh et al. 1991; Englkes and Windels 1996; Harveson 2009). \u003c/p\u003e\n\u003cp\u003eIn the recent past, it has been reported that the bottle gourd seedlings at emergence has increased in location including Manikganj, Tangail, Netrokona, Jamalpur, Rangpur, Niphamari, Savar, and Norshingdi areas. Identification of the seedling damping off disease in cucurbits was confirmed only based on host symptoms. We have studied the morphological features of the \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG 2-2IIIB followed by microscopy, pathogenicity and molecular characterization through multilocus sequence typing. To our knowledge, this is the first report of \u003cem\u003eR. solani\u003c/em\u003e AG-2-2 IIIB causes seedling damping off bottle gourd in Bangladesh. This finding will be useful to design an effective disease management program to ensure economic production of cucurbits in Bangladesh.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thanks Sher-e-Bangla Agricultural University Research System (SAURES) and Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDr. Md Ziaur Rahman Bhuiyan\u003c/strong\u003e: Conceptualization, investigation, supervision, resources and writing \u0026ndash; original draft. \u003cstrong\u003eMahmuda Akter\u003c/strong\u003e: Writing \u0026ndash; review \u0026amp; editing. Dr. \u003cstrong\u003eNazneen Sultana\u003c/strong\u003e: Writing\u0026ndash;review \u0026amp; editing. \u003cstrong\u003eMd. Jahidul Islam\u003c/strong\u003e: Writing \u0026ndash; review \u0026amp; editing. \u003cstrong\u003eMd. Akash Miah\u003c/strong\u003e: Isolation, microscopy, and identification of the pathogen, and \u003cstrong\u003eMd. Ferdous Alom\u003c/strong\u003e: Isolation, microscopy, and identification of the pathogen.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis article does not contain any studies with human participants or animals performed by any of the authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAktaruzzaman Md., Afroz T, Lee Y, Kim V (2019) \u003cem\u003eBotrytis cinerea\u003c/em\u003e Causing Gray Mold on Bottle Gourd (\u003cem\u003eLagenaria siceraria\u003c/em\u003e) in Korea. Plant Dis 103(12):3285-3285\u003c/li\u003e\n\u003cli\u003eAnderson NA (1982) The genetics and pathology of \u003cem\u003eRhizoctonia solani\u003c/em\u003e. Annu Rev Phytopathol 20:329-347\u003c/li\u003e\n\u003cli\u003eAnitha A, Das MA (2011) Activation of rice plant growth against \u003cem\u003eRhizoctonia solani\u003c/em\u003e using \u003cem\u003ePseudomonas fluorescens\u003c/em\u003e, \u003cem\u003eTrichoderma\u003c/em\u003e and salicylic acid. Res Biotechnol 2(4):12\u003c/li\u003e\n\u003cli\u003eAydin MH (2022) \u003cem\u003eRhizoctonia solani\u003c/em\u003e and Its Biological Control. T\u0026uuml;rkiye Tarımsal Araştırmalar Dergisi 9(1): 118\u0026ndash;135. https://doi.org/10.19159/tutad.1004550\u003c/li\u003e\n\u003cli\u003eBaker KF (1970) Types of Rhizoctonia diseases and their occurrence. Pages 125-148 in: \u003cem\u003eRhizoctonia solani\u003c/em\u003e: Biology and Pathology. J. R. Parmeter, Jr., ed. University of California Press, Berkeley, CA\u003c/li\u003e\n\u003cli\u003eBartlett DW, Clough JM, Godwin JR, Hall AA, Hamer M, Parr‐Dobrzanski B (2002) The strobilurin fungicides. Pest Manag. Sci. 58:649-662\u003c/li\u003e\n\u003cli\u003eEngelkes CA, Windels CE (1996) Susceptibility of sugar beet and beans to \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG-2-2 IIIB and AG-2-2 IV. Plant Dis 80:1413-1417\u003c/li\u003e\n\u003cli\u003eFarhaoui A, Alami NEl, Khadiri M, Ezrari S, Radouane N, Baala M, Tahiri A, Lahlali R (2023) Biological control of diseases caused by \u003cem\u003eRhizoctonia solan\u003c/em\u003ei AG-2-2 in sugar beet (\u003cem\u003eBeta vulgaris\u003c/em\u003e L.) using plant growth-promoting rhizobacteria (PGPR). Physiol mol plant pathol 124:101966\u003c/li\u003e\n\u003cli\u003eFRAC (2024) Fungicide Resistance Action Committee Code List 2024: Fungal control agents sorted by cross-resistance pattern and mode of action (including coding for FRAC Groups on product labels). \u003c/li\u003e\n\u003cli\u003eGlass NL, Donaldson GC (1995) Development of primer sets designed for use with the PCR to amplify conserved genes from filamentous ascomycetes. Appl Environ Microbiol 61(4): 1323-1330\u003c/li\u003e\n\u003cli\u003eHarveson RM (2009) Seedling diseases. Pages 21-24 in: Compendium of Beet Diseases and Pests. R. M. Harveson, L. E. Hanson, and G. L. Hein, eds. APS Press, St. Paul, MN\u003c/li\u003e\n\u003cli\u003eHeiser CB (1979) The Gourd Book (Univ of Oklahoma Press, Norman, OK)\u003c/li\u003e\n\u003cli\u003eKistler L, Montenegro A, Smith BD, Gifford JA, Green RE, Newsom LA, Shapiro B (2014) Transoceanic drift and the domestication of African bottle gourds in the Americas. Proc Natl Acad Sci USA. 111(8):2937-41 \u003c/li\u003e\n\u003cli\u003eLiu Y, Khan MF (2016a) Utility of fungicides for controlling \u003cem\u003eRhizoctonia solani\u003c/em\u003e on sugar beet. J Crop Prot 5:33-38\u003c/li\u003e\n\u003cli\u003eO\u0026apos;Donnell K, Sutton DA, Rinaldi MG, et al. (2009) Internet-accessible DNA sequence database for identifying fusaria from human and animal infections. J Clin Microbiol 48(10):3708-18\u003c/li\u003e\n\u003cli\u003ePaulitz TC, Okubara PA, Schillinger WF (2006) First report of damping-off of canola caused by \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG 2-1 in Washington State. Plant Dis 90:829 \u003c/li\u003e\n\u003cli\u003eRahaman ASH (2003) Bottle gourd (\u003cem\u003eLagenaria siceraria\u003c/em\u003e) - A vegetable for good health, Natural Product Radiance 2(5): 249- 256\u003c/li\u003e\n\u003cli\u003eRichardson JBI (1972) The pre-Columbian distribution of the bottle gourd (\u003cem\u003eLagenaria siceraria\u003c/em\u003e): A re-evaluation. Econ Bot 26(3):265\u0026ndash;273\u003c/li\u003e\n\u003cli\u003eSalazar O, Julian MC, Hyakumachi M, Rubio V (2000) Phylogenetic grouping of cultural types of \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG2-2 based on ribosomal ITS sequences. Mycologia 92:505-509\u003c/li\u003e\n\u003cli\u003eSean M, Toporek and Keinath AP (2021) A Diagnostic Guide for Pythium Damping-Off and Root and Stem Rot of Cucurbits. Plant Health Progress. 22(3):415-418\u003c/li\u003e\n\u003cli\u003eSharon M, Kuninaga S, Hyakumachi M, Sneh, B (2006) The advancing identification and classification of \u003cem\u003eRhizoctonia\u003c/em\u003e spp. using molecular and biotechnological methods compared with the classical anastomosis grouping. Mycoscience 47:299-316\u003c/li\u003e\n\u003cli\u003eSneh B, Burpee L, Ogoshi A (1991) Identification of \u003cem\u003eRhizoctonia\u003c/em\u003e species. APS Press, St. Paul. MN, USA\u003c/li\u003e\n\u003cli\u003eVerdoodt F (2023) Biological Control of \u003cem\u003eRhizoctonia solani\u003c/em\u003e in Field Bean (\u003cem\u003eVicia faba\u003c/em\u003e L.) using cyclic Lipopeptide-producing Bacteria. Master\u0026rsquo;s Dissertation, Ghent University, Belgium\u003c/li\u003e\n\u003cli\u003eWhite TJ, Bruns, TD, Lee SB, Taylor JW (1990) PCR Protocols: A Guide to Methods and Applications, Academic Press, New York. Pp 315-322\u003c/li\u003e\n\u003cli\u003eZitter TA, Hopkins DL, Thomas CE (1996) Compendium of Cucurbit Diseases. American Phytopathological Society Press, St. Paul, MN.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003eTable 1. Primers were used in this study.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"654\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocus\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrimer\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrimer Sequence (\u003c/strong\u003e\u003cstrong\u003e5\u0026apos;-3\u0026apos;)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 190px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eReference\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003eITS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eITS1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e5\u0026apos;-TCCGTAGGTGAACCTGCGG-3\u0026apos;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 190px;\"\u003e\n \u003cp\u003eWhite et al. 1990\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eITS4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e5\u0026apos;-TCCTCCGCTTATTGATATGC-3\u0026apos;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e\u003cem\u003erpb2\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e5F2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e5\u0026apos;- GGGGWGAYCAGAAGAAGGC-3\u0026apos;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 190px;\"\u003e\n \u003cp\u003eO\u0026apos;Donnell et al. 2010\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e7cR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e5\u0026apos;- CCCATRGCTTGYTTRCCCAT-3\u0026apos;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e\u003cem\u003etub2\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eBt2a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e5\u0026apos;-GGTAACCAAATCGGTGCTGCTTTC-3\u0026apos;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 190px;\"\u003e\n \u003cp\u003eGlass and Donaldson 1995\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eBt2b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 324px;\"\u003e\n \u003cp\u003e5\u0026apos;-ACCCTCAGT GTAGTG ACC CTTGGC-3\u0026apos;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Fungus, soil borne, seedling diseases, bottle gourd, ITS, rpb2, tub2","lastPublishedDoi":"10.21203/rs.3.rs-8263008/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8263008/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBottle gourd is a popular winter vegetable crop in Bangladesh. Bottle gourd seedlings with damping off symptoms were collected in October 2024 from Savar upazila, Dhaka. The causal agent was grown in growth media, and studied the morphological features. Molecular identity was confirmed through amplification of internal-transcribed spacer (ITS) region, RNA polymerase II (\u003cem\u003erpb2\u003c/em\u003e), and β-tubulin (\u003cem\u003etub2\u003c/em\u003e) genes. Based on morphological and molecular investigations, the pathogen was verified as \u003cem\u003eRhizoctonia solani\u003c/em\u003e AG 2\u0026ndash;2 IIIB. Pathogenicity test was done to fulfill the Koch\u0026rsquo;s postulates. These findings will be useful to design an effective disease management program of cucurbits in Bangladesh.\u003c/p\u003e","manuscriptTitle":"First Report of Rhizoctonia solani AG 2-2IIIB causing Damping-off on Bottle Gourd (Lagenaria siceraria) Seedlings in Bangladesh","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-16 13:47:50","doi":"10.21203/rs.3.rs-8263008/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"73604032-0053-45a3-9ad4-eea67dc2bb3f","owner":[],"postedDate":"December 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-28T00:27:22+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-16 13:47:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8263008","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8263008","identity":"rs-8263008","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}