The core clock transcription factor TOC1 is a direct regulator of immunity in Arabidopsis

The core clock transcription factor TOC1 is a direct regulator of immunity in Arabidopsis | 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 The core clock transcription factor TOC1 is a direct regulator of immunity in Arabidopsis Shannon-Leigh Sparks, Laura C. Roden, Robert A. Ingle This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7000350/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Feb, 2026 Read the published version in Communications Biology → Version 1 posted You are reading this latest preprint version Abstract The plant circadian clock drives temporal differences in susceptibility to pathogens. We investigated the role of TIMING OF CAB EXPRESSION 1 (TOC1) in the regulation of defence against Botrytis cinerea in Arabidopsis. The temporal variation in susceptibility to B. cinerea observed in wild-type Arabidopsis was abolished in TOC1-ox and toc1-2 plants under both diurnal and constant conditions. In addition, TOC1-ox plants were more susceptible than Col-0 following inoculation at dawn, while inoculation at night lead to enhanced resistance in toc1-2 plants versus C24 plants, suggesting TOC1 is a negative regulator of immunity. RNA-seq analysis showed that the genes mis-regulated in toc1-2 plants had significant enrichment for terms related to biotic stress, an overrepresentation of G-box elements in their promoters, and included genes encoding key transcription factors (TFs) involved in defence against necrotrophic pathogens. Chromatin immunoprecipitation-qPCR showed that TOC1 occupies G-box containing regions of the defence TFs ERF4 , ORA47 , ORA59 and WRKY33 in a pathogen-responsive and MYC2-dependent manner. We suggest that the phased TOC1 occupancy of defence gene promoters contributes to the gating of plant immunity against necrotrophic pathogens, while the MYC2-dependent release of TOC1 in response to pathogen detection allows plants to mount an acute immune response. Biological sciences/Molecular biology/Transcriptomics Biological sciences/Plant sciences/Plant immunity/Virulence Biological sciences/Plant sciences/Plant molecular biology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementalmethods.pdf Supplementary methods Supplementaltables.xlsx Supplementary tables S1-S11 Suppfigures.pdf Supplementary figures Cite Share Download PDF Status: Published Journal Publication published 11 Feb, 2026 Read the published version in Communications Biology → Version 1 posted 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-7000350","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":483646135,"identity":"e1de7ac0-43bd-4af6-ac93-0c76dff3aa7b","order_by":0,"name":"Shannon-Leigh Sparks","email":"","orcid":"https://orcid.org/0000-0002-3110-7084","institution":"Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa; Current address: International Centre for Genetic Engineering and Biotechnology Cape Town, Observatory, South Africa","correspondingAuthor":false,"prefix":"","firstName":"Shannon-Leigh","middleName":"","lastName":"Sparks","suffix":""},{"id":483646136,"identity":"a40e0b91-fcfe-435f-8b2b-010efd634b4a","order_by":1,"name":"Laura C. 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We investigated the role of TIMING OF CAB EXPRESSION 1 (TOC1) in the regulation of defence against \u003ci\u003eBotrytis cinerea\u003c/i\u003e in Arabidopsis. The temporal variation in susceptibility to \u003ci\u003eB. cinerea\u003c/i\u003e observed in wild-type Arabidopsis was abolished in \u003ci\u003eTOC1-ox\u003c/i\u003e and \u003ci\u003etoc1-2\u003c/i\u003e plants under both diurnal and constant conditions. In addition, \u003ci\u003eTOC1-ox\u003c/i\u003e plants were more susceptible than Col-0 following inoculation at dawn, while inoculation at night lead to enhanced resistance in \u003ci\u003etoc1-2\u003c/i\u003e plants versus C24 plants, suggesting TOC1 is a negative regulator of immunity. RNA-seq analysis showed that the genes mis-regulated in \u003ci\u003etoc1-2\u003c/i\u003e plants had significant enrichment for terms related to biotic stress, an overrepresentation of G-box elements in their promoters, and included genes encoding key transcription factors (TFs) involved in defence against necrotrophic pathogens. Chromatin immunoprecipitation-qPCR showed that TOC1 occupies G-box containing regions of the defence TFs \u003ci\u003eERF4\u003c/i\u003e, \u003ci\u003eORA47\u003c/i\u003e, \u003ci\u003eORA59\u003c/i\u003e and \u003ci\u003eWRKY33\u003c/i\u003e in a pathogen-responsive and MYC2-dependent manner. We suggest that the phased TOC1 occupancy of defence gene promoters contributes to the gating of plant immunity against necrotrophic pathogens, while the MYC2-dependent release of TOC1 in response to pathogen detection allows plants to mount an acute immune response.","manuscriptTitle":"The core clock transcription factor TOC1 is a direct regulator of immunity in Arabidopsis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-16 04:37:23","doi":"10.21203/rs.3.rs-7000350/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"communications-biology","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"commsbio","sideBox":"Learn more about [Communications Biology](http://www.nature.com/commsbio/)","snPcode":"","submissionUrl":"","title":"Communications Biology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Communications Series","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"735bb80b-bf17-483d-9148-c696974aeaa4","owner":[],"postedDate":"July 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":51354630,"name":"Biological sciences/Molecular biology/Transcriptomics"},{"id":51354631,"name":"Biological sciences/Plant sciences/Plant immunity/Virulence"},{"id":51354632,"name":"Biological sciences/Plant sciences/Plant molecular biology"}],"tags":[],"updatedAt":"2026-03-20T07:46:34+00:00","versionOfRecord":{"articleIdentity":"rs-7000350","link":"https://doi.org/10.1038/s42003-026-09667-y","journal":{"identity":"communications-biology","isVorOnly":false,"title":"Communications Biology"},"publishedOn":"2026-02-11 05:00:00","publishedOnDateReadable":"February 11th, 2026"},"versionCreatedAt":"2025-07-16 04:37:23","video":"","vorDoi":"10.1038/s42003-026-09667-y","vorDoiUrl":"https://doi.org/10.1038/s42003-026-09667-y","workflowStages":[]},"version":"v1","identity":"rs-7000350","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7000350","identity":"rs-7000350","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}