Absence of Phytophthora species in naturally regenerated European beech seedlings

Absence of Phytophthora species in naturally regenerated European beech seedlings | 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 Absence of Phytophthora species in naturally regenerated European beech seedlings Elham Badalzadehe Aghdam, Carmen Romeralo, Dániel G. Knapp, Johanna Witzell This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9579201/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 Soilborne oomycetes of the genus Phytophthora are an increasing concern in European beech ( Fagus sylvatica ) forests, where they can damage root systems and contribute to tree decline. Because Phytophthora inoculum may persist in soil and is difficult to eradicate once established, naturally regenerated seedlings in affected stands may be exposed to infection during early development. At the same time, natural regeneration may reduce some biosecurity risks associated with planting nursery stock, a recognized pathway for Phytophthora spread. However, there is still limited understanding of how early Phytophthora infects naturally regenerated beech, including during the seed and early seedling stages, in stands with a history of pathogen presence. We examined culturable fungi and oomycetes associated with 91 naturally regenerated beech seedlings and 30 beech seeds collected from a protected beech forest in southern Sweden with previous records of Phytophthora . Seedling condition was assessed using root and foliar symptoms, and isolates that were cultured in selective media from seedling roots and seeds were identified using ITS rDNA sequencing. Root lesions were common and were associated with poorer seedling condition, but Phytophthora isolates were not recovered from either seedling roots or seeds. Instead, seedling roots yielded 361 culturable isolates dominated by Clonostachys sp., Metapochonia bulbillosa , and Aspergillus sp. Seeds yielded 73 isolates, with 34 ITS sequences representing 11 taxa, mainly Linnemannia , Fusarium , and Clonostachys taxa. Our results indicate that root damage in naturally regenerated beech seedlings was not associated with any Phytophthora species. Further work is needed to clarify whether Phytophthora persists at low levels or if other soil fungi are more persistent during early regeneration stages. Fagus sylvatica forest regeneration Phytophthora natural regeneration oomycetes Full Text Supplementary Files Supplementarytable5.docx SupplementaryTableS1Seedlingisolates.docx SupplementaryTableS2Seedisolates.docx TableS3.xlsx TableS4.xlsx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 12 May, 2026 Reviewers invited by journal 08 May, 2026 Editor invited by journal 06 May, 2026 Editor assigned by journal 04 May, 2026 First submitted to journal 01 May, 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-9579201","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":636763892,"identity":"5d598644-07c6-4f25-90aa-ce3a592b4ab3","order_by":0,"name":"Elham Badalzadehe Aghdam","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA40lEQVRIiWNgGAWjYDACdh4IbcCQwMDwoYAYLcxIWhhnGJCqhZmHGC38zLwHP91gsLPbzp78dLONwZ3EBv7DB/BqkWzmS5bOYUhO3tnzzOx2jsGzxAaJtAS8WgwO8xgAtTAnG9xIAGk5DNRCwHn2h3mMf+cw1AO1pH+7bQHSwn/+A35bmHnMgLYctjO4kWN2mwGkhSEHrw4GicM8ZtY5BscTDM68KbvZY3DYuE0iDb/D+Nt7jG/nVFTbGxxP33bjR8Vh2X7+ww/wWwNxHgPQPVDARoR6MLAnVuEoGAWjYBSMQAAAyXVFI2YXbSsAAAAASUVORK5CYII=","orcid":"","institution":"Linnaeus University - Vaxjo Campus: Linneuniversitet - Vaxjo","correspondingAuthor":true,"prefix":"","firstName":"Elham","middleName":"Badalzadehe","lastName":"Aghdam","suffix":""},{"id":636763893,"identity":"95fdc67f-d47a-436c-b504-b230fac95dae","order_by":1,"name":"Carmen Romeralo","email":"","orcid":"","institution":"INIA: Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria","correspondingAuthor":false,"prefix":"","firstName":"Carmen","middleName":"","lastName":"Romeralo","suffix":""},{"id":636763894,"identity":"e96f0b22-39c7-495a-9861-d35ded180a18","order_by":2,"name":"Dániel G. 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Pathology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Fagus sylvatica, forest regeneration, Phytophthora, natural regeneration, oomycetes","lastPublishedDoi":"10.21203/rs.3.rs-9579201/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9579201/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSoilborne oomycetes of the genus \u003cem\u003ePhytophthora\u003c/em\u003e are an increasing concern in European beech (\u003cem\u003eFagus sylvatica\u003c/em\u003e) forests, where they can damage root systems and contribute to tree decline. Because \u003cem\u003ePhytophthora\u003c/em\u003e inoculum may persist in soil and is difficult to eradicate once established, naturally regenerated seedlings in affected stands may be exposed to infection during early development. At the same time, natural regeneration may reduce some biosecurity risks associated with planting nursery stock, a recognized pathway for \u003cem\u003ePhytophthora\u003c/em\u003e spread. However, there is still limited understanding of how early \u003cem\u003ePhytophthora\u003c/em\u003e infects naturally regenerated beech, including during the seed and early seedling stages, in stands with a history of pathogen presence. We examined culturable fungi and oomycetes associated with 91 naturally regenerated beech seedlings and 30 beech seeds collected from a protected beech forest in southern Sweden with previous records of \u003cem\u003ePhytophthora\u003c/em\u003e. Seedling condition was assessed using root and foliar symptoms, and isolates that were cultured in selective media from seedling roots and seeds were identified using ITS rDNA sequencing. Root lesions were common and were associated with poorer seedling condition, but \u003cem\u003ePhytophthora\u003c/em\u003e isolates were not recovered from either seedling roots or seeds. Instead, seedling roots yielded 361 culturable isolates dominated by \u003cem\u003eClonostachys\u003c/em\u003e sp., \u003cem\u003eMetapochonia bulbillosa\u003c/em\u003e, and \u003cem\u003eAspergillus\u003c/em\u003e sp. Seeds yielded 73 isolates, with 34 ITS sequences representing 11 taxa, mainly \u003cem\u003eLinnemannia\u003c/em\u003e, \u003cem\u003eFusarium\u003c/em\u003e, and \u003cem\u003eClonostachys\u003c/em\u003e taxa. Our results indicate that root damage in naturally regenerated beech seedlings was not associated with any \u003cem\u003ePhytophthora\u003c/em\u003e species. Further work is needed to clarify whether \u003cem\u003ePhytophthora\u003c/em\u003e persists at low levels or if other soil fungi are more persistent during early regeneration stages.\u003c/p\u003e","manuscriptTitle":"Absence of Phytophthora species in naturally regenerated European beech seedlings","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-18 21:50:15","doi":"10.21203/rs.3.rs-9579201/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2026-05-12T11:17:10+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-08T09:15:57+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"European Journal of Plant Pathology","date":"2026-05-07T03:50:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-04T05:13:21+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Plant Pathology","date":"2026-05-01T08:05:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-plant-pathology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejpp","sideBox":"Learn more about [European Journal of Plant Pathology](http://link.springer.com/journal/10658)","snPcode":"10658","submissionUrl":"https://www.editorialmanager.com/ejpp/default2.aspx","title":"European Journal of Plant Pathology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4f7e3f4d-3cc3-468f-8b65-776a632a34be","owner":[],"postedDate":"May 18th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"","date":"2026-05-12T11:17:10+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-08T09:15:57+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"European Journal of Plant Pathology","date":"2026-05-07T03:50:23+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-18T21:50:15+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-18 21:50:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9579201","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9579201","identity":"rs-9579201","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}