{"paper_id":"cb321da8-5cda-4b74-b428-74ff46051d28","body_text":"Low soil phosphorus conditioning enhances mutualism in Rhizophagus irregularis regardless of nuclear organization, even when conditions shift | 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 Low soil phosphorus conditioning enhances mutualism in Rhizophagus irregularis regardless of nuclear organization, even when conditions shift Pedro Madeira Antunes, Catherine Fahey, Nicolas Corradi, Vasilis Kokkoris This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5830594/v2 This work is licensed under a CC BY 4.0 License Status: Posted Version 2 posted You are reading this latest preprint version Show more versions Abstract Strains of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis belong to one of two nuclear organizations: homokaryons, which carry genetically similar nuclei, and dikaryons, which harbour two genetically distinct nuclear populations. Although traits tend to be conserved within each group, it is unclear whether these groups differ in their capacity to adapt or exhibit phenotypic plasticity in response to environmental change. Here, we tested whether dikaryotic strains have greater potential than homokaryotic strains for rapid adaptation or plasticity in response to shifts in soil phosphorus (P) availability. The experiment comprised two phases. In the conditioning phase, the growth responses of Allium ampeloprasum L. inoculated with four homokaryotic or four dikaryotic strains were measured under contrasting soil P levels. In the adaptive potential phase, conditioned strains were grown under P conditions that either matched (home) or differed from (away) those in the conditioning phase to assess whether prior P exposure influenced subsequent mutualistic functioning. During conditioning, dikaryotic strains were more mutualistic than homokaryotic strains under high P, promoting greater host biomass. In the adaptive potential phase, strains conditioned under low P enhanced host biomass significantly more than those conditioned under high P in both Phase 2 P environments, a pattern consistent across all biomass metrics. This effect did not differ between dikaryons and homokaryons. Together, these results provide the first direct evidence that conditioning AM fungi under low soil P can enhance their subsequent benefits to host plants, even when P availability increases. Soil P conditioning strategies for AM fungi therefore merit consideration in agriculture and other managed ecosystems. Mycology Agroecology Population Biology AMF adaptability Rhizophagus irregularis strains soil fertility genome organization intraspecific variability phenotypic plasticity soil P levels shifting environmental conditions Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 2 posted You are reading this latest preprint version Show more versions 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-5830594\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":424309919,\"identity\":\"e5dcccd1-2685-4c57-a49f-e05238b68e35\",\"order_by\":0,\"name\":\"Pedro Madeira 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