In Vitro Culture and Draft Genome Assembly of Monographella maydis Predict a Molecular Driver of Its Sexual Fitness in Maize Tar Spot Disease

In Vitro Culture and Draft Genome Assembly of Monographella maydis Predict a Molecular Driver of Its Sexual Fitness in Maize Tar Spot Disease | 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 In Vitro Culture and Draft Genome Assembly of Monographella maydis Predict a Molecular Driver of Its Sexual Fitness in Maize Tar Spot Disease Akshaya K. Biswal, Susana D. Arteaga-Quiroz, Sameer Pokhrel, Irma Martínez, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9543400/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Tar Spot Complex (TSC) is a devastating foliar disease of maize that threatens global food security, causing yield losses of up to 50%. While the disease is initiated by Phyllachora maydis , the "fisheye" necrosis that intensifies disease severity is attributed to Monographella maydis . Historically, the precise role of M. maydis has remained elusive due to a lack of reliable in vitro culture systems and genomic resources. This study reports the first successful isolation and reproducible in vitro culture of M. maydis , identifying V8 agar as an optimal medium for mycelial growth and sporulation. Using PacBio long-read sequencing technology, we generated a high-quality 39.8 Mb genome assembly for M. maydis , predicting 10,228 protein coding genes, 227 non-coding RNAs, 175 tRNAs and 45 rRNAs. Functional annotation identified a diverse repertoire of secreted proteins and multiple biosynthetic gene clusters, likely involved in the tar spot disease pathosystem interaction. Phylogenomic analysis confirmed that M. maydis is distinct from P. maydis , supporting a synergistic rather than evolutionary relationship between the two fungi. Furthermore, the identification of a conserved adenosine deaminase residue (H352) suggests potential for A-to-I RNA editing during sexual reproduction. Finally, we report the use of ITS1 and ITS4 primer pair for successful detection of M. maydis from infected leaf tissues. These findings provide a foundational genomic and microbiological framework for improving molecular diagnostics and developing effective management strategies to mitigate the economic impact of TSC on maize production. Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementarytable4Functionalanalysisfinal.xlsx Supplementarymaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 07 May, 2026 Editor invited by journal 04 May, 2026 Editor assigned by journal 30 Apr, 2026 Submission checks completed at journal 30 Apr, 2026 First submitted to journal 27 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9543400","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":640524012,"identity":"907a88de-87c3-42e8-a12d-84c30b2c569c","order_by":0,"name":"Akshaya K. 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While the disease is initiated by \u003cem\u003ePhyllachora maydis\u003c/em\u003e, the \"fisheye\" necrosis that intensifies disease severity is attributed to \u003cem\u003eMonographella maydis\u003c/em\u003e. Historically, the precise role of \u003cem\u003eM. maydis\u003c/em\u003e has remained elusive due to a lack of reliable \u003cem\u003ein vitro\u003c/em\u003e culture systems and genomic resources. This study reports the first successful isolation and reproducible \u003cem\u003ein vitro\u003c/em\u003e culture of \u003cem\u003eM. maydis\u003c/em\u003e, identifying V8 agar as an optimal medium for mycelial growth and sporulation.\u003c/p\u003e \u003cp\u003eUsing PacBio long-read sequencing technology, we generated a high-quality 39.8 Mb genome assembly for \u003cem\u003eM. maydis\u003c/em\u003e, predicting 10,228 protein coding genes, 227 non-coding RNAs, 175 tRNAs and 45 rRNAs. Functional annotation identified a diverse repertoire of secreted proteins and multiple biosynthetic gene clusters, likely involved in the tar spot disease pathosystem interaction. Phylogenomic analysis confirmed that \u003cem\u003eM. maydis\u003c/em\u003e is distinct from \u003cem\u003eP. maydis\u003c/em\u003e, supporting a synergistic rather than evolutionary relationship between the two fungi. Furthermore, the identification of a conserved \u003cem\u003eadenosine deaminase\u003c/em\u003e residue (H352) suggests potential for A-to-I RNA editing during sexual reproduction. Finally, we report the use of ITS1 and ITS4 primer pair for successful detection of \u003cem\u003eM. maydis\u003c/em\u003e from infected leaf tissues. 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