Plant growth promotion and biocontrol by novel thermotolerant fungal strains isolated from an active volcano crater

Plant growth promotion and biocontrol by novel thermotolerant fungal strains isolated from an active volcano crater | 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 Article Plant growth promotion and biocontrol by novel thermotolerant fungal strains isolated from an active volcano crater Amanda Martirena-Ramírez, Claribel Orquídea Zenteno-Alegría, Yordanis Pérez-Llano, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9013473/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Microorganisms present in the rhizosphere of plants from extreme environments have become a subject of great interest as an alternative to chemical fertilizers for sustainable agriculture. This study focused on the isolation, identification and characterization of extremophilic rhizospheric fungi strains present in a habitat with challenging environmental conditions in terms of temperature, pH, and heavy metal concentrations. Studies were conducted with the aim of finding new microorganisms for the development of novel, robust inoculants that meet the agricultural needs of Solanum lycopersicum , a crop consumed worldwide that, at least in Mexico can be exposed to heat shock in certain seasons. All the strains showed at least five plant growth promoting traits. Noticeably two of the isolated strains (R_34 and R_40) produced indole related compounds (probably indoleacetic acid (IAA)); others hydrolytic enzymes (cellulases, xylanases, and chitinases), as well as siderophores and showed the ability to solubilize inorganic phosphate. All strains reduced the progression of infection caused by Botrytis cinerea on S. lycopersicum leaves and fruits compared to the control, and they also inhibited the growth of various phytopathogenic fungi under in vitro conditions, suggesting an important role in biological control. The microorganisms were identified at the species level through phylogenetic analysis. The fungal strains belonged to the genus Trichoderma sp., Penicillium sp., and Aspergillus sp. In addition, these fungi demonstrated the ability to enhance germination rates, and overall plant growth in S. lycopersicum compared to controls. This research demonstrates that extremophilic fungi can serve as effective probiotics for crops, allegedly in regions affected by climate variability and heatwaves. Biological sciences/Biotechnology Biological sciences/Microbiology Biological sciences/Plant sciences abiotic stress Aspergillus biological control Penicillium plant growth promotion Trichoderma Full Text Additional Declarations No competing interests reported. Supplementary Files Suplementarymaterials.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 16 Apr, 2026 Reviews received at journal 09 Apr, 2026 Reviews received at journal 29 Mar, 2026 Reviewers agreed at journal 27 Mar, 2026 Reviewers agreed at journal 24 Mar, 2026 Reviewers invited by journal 23 Mar, 2026 Editor assigned by journal 23 Mar, 2026 Editor invited by journal 10 Mar, 2026 Submission checks completed at journal 05 Mar, 2026 First submitted to journal 05 Mar, 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-9013473","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":611537132,"identity":"40244bcb-0b19-4dd2-8bdc-7faf9dca49b0","order_by":0,"name":"Amanda Martirena-Ramírez","email":"","orcid":"","institution":"Universidad Autónoma del Estado de Morelos","correspondingAuthor":false,"prefix":"","firstName":"Amanda","middleName":"","lastName":"Martirena-Ramírez","suffix":""},{"id":611537133,"identity":"806f3e07-33d8-4dcb-b8c1-034a5c441940","order_by":1,"name":"Claribel Orquídea Zenteno-Alegría","email":"","orcid":"","institution":"Universidad 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