Integrated biological and chemical strategies for sustainable management of Nigrospora coryli-induced tobacco leaf spot

Integrated biological and chemical strategies for sustainable management of Nigrospora coryli-induced tobacco leaf spot | 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 Integrated biological and chemical strategies for sustainable management of Nigrospora coryli-induced tobacco leaf spot Jingpei Zou, Liuti Cai, Yiming Geng, Mengyu Yin, Yuguang Mu, Jingjing Guo, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9462624/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 Tobacco (Nicotiana tabacum) leaf spot disease caused by fungal pathogens poses a major threat to crop yield and quality worldwide. Recently, Nigrospora coryli was identified as a novel causal agent of tobacco leaf spot in China, yet its biology, ecological interactions, and management strategies remained largely unexplored. In this study, we systematically characterized N. coryli through growth physiology, environmental adaptability, phyllosphere microbiome profiling, microbial interactions, and fungicide sensitivity assays. The pathogen exhibited robust environmental tolerance, with optimal growth at 28°C and pH 6.0, viability across pH 4–11, and survival at temperatures up to 57°C, while preferring soluble starch and peptone as nutrient sources. High-throughput sequencing revealed disease-associated phyllosphere shifts, including enrichment of Stenotrophomonas and Pseudomonas in symptomatic leaves and the exclusive detection of Nigrospora and Sarocladium in diseased tissues. Functional screening identified multiple antagonistic microbes, with Aspergillus niger MGM reducing lesion size by 87.6% in planta, while Pseudomonas syringae pv. angulata SLB-5-3 exacerbated disease. Among eight commercial fungicides, fludioxonil was the most potent (EC₅₀ = 0.0057 μg/mL), followed by the prochloraz-manganese chloride complex, difenoconazole, and fenaminstrobin. Synergistic interactions were observed in binary mixtures: fludioxonil + difenoconazole (1:4, SR = 1.7360), fludioxonil + fenaminstrobin (1:1, SR = 1.5365), and difenoconazole + fenaminstrobin (1:2, SR = 2.0219). These findings highlight the potential of integrating potent biocontrol agents with synergistic fungicide combinations for sustainable management of N. coryli-induced tobacco leaf spot. This study provides a comprehensive foundation for developing environmentally sound, multifaceted disease control strategies. Tobacco leaf spot Nigrospora coryli biological characterization phyllosphere microbial community biocontrol fungicide synergy Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 22 Apr, 2026 Reviewers agreed at journal 20 Apr, 2026 Reviewers invited by journal 20 Apr, 2026 Editor assigned by journal 20 Apr, 2026 Submission checks completed at journal 20 Apr, 2026 First submitted to journal 19 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-9462624","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":628157131,"identity":"ea7fee2b-8ead-4fa3-a977-5a26caf344aa","order_by":0,"name":"Jingpei Zou","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Jingpei","middleName":"","lastName":"Zou","suffix":""},{"id":628157132,"identity":"ec3373eb-3cbb-49d1-9849-e08dd7bef2ef","order_by":1,"name":"Liuti 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