High light-induced phosphorylation of Lhcb6 (CP24) enhances non-photochemical quenching dependent on the PSI-PSII megacomplexes

High light-induced phosphorylation of Lhcb6 (CP24) enhances non-photochemical quenching dependent on the PSI-PSII megacomplexes | 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 High light-induced phosphorylation of Lhcb6 (CP24) enhances non-photochemical quenching dependent on the PSI-PSII megacomplexes Yang Chunhong, lishuan wu, Yajun Lin, Xinguang Zhu, Yuanming Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7613824/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Plants have evolved diverse photoprotective mechanisms to cope with fluctuating light environments, among which non-photochemical quenching (NPQ) plays a central role in dissipating excess excitation energy and preventing photosystem II (PSII) damage. While the molecular basis of NPQ is well established in model species such as Arabidopsis thaliana, its regulation in non-model plants remains less understood, offering untapped potential for discovering novel photoprotective strategies. Here, we report a previously unrecognized mechanism in angiosperms Berteroa incana: high-light (HL)-induced phosphorylation of the minor antenna protein CP24 (Lhcb6), specifically at Thr178, serves as a critical regulator of NPQ, a close relative of Arabidopsis thaliana with exceptional phototolerance. Unlike LHCII phosphorylation mediated by STN7 kinases, CP24 phosphorylation is governed by a distinct kinase system and is selectively dephosphorylated by the phosphatase rPBCP. Using biochemical and functional analyses, we demonstrate that phosphorylated CP24 (P-CP24) predominantly resides within the PSII-PSI megacomplex (mc1), where it facilitates efficient energy transfer from CP47 to PSI. This mechanism drives a previously unreported Zeaxanthin- and Lutein-independent fluorescence quenching pathway under HL conditions in terrestrial plants. Our results suggest that P-CP24 enhances PSII photoprotection by dynamically redirecting excess excitation energy away from PSII reaction centers, thereby reducing reactive oxygen species (ROS) production, maintaining PSII activity, and optimizing energy utilization under stress. Biological sciences/Plant sciences/Plant stress responses/Light stress Biological sciences/Plant sciences/Photosynthesis/Non-photochemical quenching CP24 phosphorylation non-photochemical quenching mc1 spillover photoprotection Full Text Additional Declarations There is NO Competing Interest. Supplementary Files supplementaryinformation.pdf Supplementary information (Figure S1-Figure S9) SupplementaryTable1.xlsx Supplementary Table 1 SupplementaryTable2.xlsx Supplementary Table 2 Cite Share Download PDF Status: Posted 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. 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-7613824","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":536485467,"identity":"bd68e0c7-4300-4bdb-b6c2-3fd2b56eb2b2","order_by":0,"name":"Yang Chunhong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAz0lEQVRIiWNgGAWjYLACxgYbHgNStaSRruUwA/FaDI6fPfzi547zMubshx9/YKixY+Cf3UBAy5m8NMveM7d5LHvSzCQYjiUzSNw5QEDLgRwzY8a22zwGNxjMGBjYDjAYSCQQ0HL+DUjLOaAW9s8fGP4Ro+VGjvFjxrYDQC08BhJABmEtkjfemDH2tiUD/ZJTJpHYl8wjcYOAFr7zOcYffrbZ2ZuzH9/84cM3Ozn+GQS0KBxgYJOA84CKefCrBwL5BgbmDwRVjYJRMApGwcgGAC3KQl+xJMBoAAAAAElFTkSuQmCC","orcid":"","institution":"Institute of Botany, Chinese Academy of Sciences","correspondingAuthor":true,"prefix":"","firstName":"Yang","middleName":"","lastName":"Chunhong","suffix":""},{"id":536485468,"identity":"f52da3ed-e281-4dd2-bc21-17e954fd1428","order_by":1,"name":"lishuan wu","email":"","orcid":"","institution":"Key Laboratory of Plant Resources/Beijing Botanical Garden, Institute of Botany, the Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"lishuan","middleName":"","lastName":"wu","suffix":""},{"id":536485469,"identity":"8b2f98c2-60da-44ca-a187-b3cec3e016c1","order_by":2,"name":"Yajun Lin","email":"","orcid":"","institution":"CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology","correspondingAuthor":false,"prefix":"","firstName":"Yajun","middleName":"","lastName":"Lin","suffix":""},{"id":536485470,"identity":"808b1b75-5b50-4c53-8058-d8d523a71414","order_by":3,"name":"Xinguang Zhu","email":"","orcid":"https://orcid.org/0000-0002-4435-130X","institution":"CAS center for excellence in molecular plant sciences","correspondingAuthor":false,"prefix":"","firstName":"Xinguang","middleName":"","lastName":"Zhu","suffix":""},{"id":536485471,"identity":"43846ca0-890a-481f-a0e3-08c64695489d","order_by":4,"name":"Yuanming Zhang","email":"","orcid":"","institution":"State Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Yuanming","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2025-09-14 16:30:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7613824/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7613824/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":96604104,"identity":"7dad13a6-a469-410d-a5d6-65c67681fb07","added_by":"auto","created_at":"2025-11-24 09:12:46","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1887320,"visible":true,"origin":"","legend":"Article File","description":"","filename":"PCP24manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7613824/v1_covered_e37c746c-d865-4436-905c-99b1054e7d4b.pdf"},{"id":94647472,"identity":"fdc3eebb-9f32-4f50-ab52-c2c2f955ef32","added_by":"auto","created_at":"2025-10-29 09:05:28","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1700988,"visible":true,"origin":"","legend":"Supplementary information (Figure S1-Figure S9)","description":"","filename":"supplementaryinformation.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7613824/v1/d6186183c194d09b1b86d8f7.pdf"},{"id":94647473,"identity":"6a8bbf57-23ad-4018-862d-baf9670e3c88","added_by":"auto","created_at":"2025-10-29 09:05:29","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1151158,"visible":true,"origin":"","legend":"Supplementary Table 1","description":"","filename":"SupplementaryTable1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7613824/v1/a30aac722404bddb3c7ba30e.xlsx"},{"id":94647471,"identity":"3950959f-4b62-4716-a0dd-d38a58f7bf0a","added_by":"auto","created_at":"2025-10-29 09:05:28","extension":"xlsx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":15041,"visible":true,"origin":"","legend":"Supplementary Table 2","description":"","filename":"SupplementaryTable2.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7613824/v1/30c7a1e0bd0c0a1b46977605.xlsx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"High light-induced phosphorylation of Lhcb6 (CP24) enhances non-photochemical quenching dependent on the PSI-PSII megacomplexes","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"CP24, phosphorylation, non-photochemical quenching, mc1, spillover, photoprotection","lastPublishedDoi":"10.21203/rs.3.rs-7613824/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7613824/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Plants have evolved diverse photoprotective mechanisms to cope with fluctuating light environments, among which non-photochemical quenching (NPQ) plays a central role in dissipating excess excitation energy and preventing photosystem II (PSII) damage. While the molecular basis of NPQ is well established in model species such as Arabidopsis thaliana, its regulation in non-model plants remains less understood, offering untapped potential for discovering novel photoprotective strategies. Here, we report a previously unrecognized mechanism in angiosperms Berteroa incana: high-light (HL)-induced phosphorylation of the minor antenna protein CP24 (Lhcb6), specifically at Thr178, serves as a critical regulator of NPQ, a close relative of Arabidopsis thaliana with exceptional phototolerance. Unlike LHCII phosphorylation mediated by STN7 kinases, CP24 phosphorylation is governed by a distinct kinase system and is selectively dephosphorylated by the phosphatase rPBCP. Using biochemical and functional analyses, we demonstrate that phosphorylated CP24 (P-CP24) predominantly resides within the PSII-PSI megacomplex (mc1), where it facilitates efficient energy transfer from CP47 to PSI. This mechanism drives a previously unreported Zeaxanthin- and Lutein-independent fluorescence quenching pathway under HL conditions in terrestrial plants. Our results suggest that P-CP24 enhances PSII photoprotection by dynamically redirecting excess excitation energy away from PSII reaction centers, thereby reducing reactive oxygen species (ROS) production, maintaining PSII activity, and optimizing energy utilization under stress.","manuscriptTitle":"High light-induced phosphorylation of Lhcb6 (CP24) enhances non-photochemical quenching dependent on the PSI-PSII megacomplexes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-29 09:05:23","doi":"10.21203/rs.3.rs-7613824/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0445ce98-968e-4464-bd6b-10ae759d4f5c","owner":[],"postedDate":"October 29th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":57045371,"name":"Biological sciences/Plant sciences/Plant stress responses/Light stress"},{"id":57045372,"name":"Biological sciences/Plant sciences/Photosynthesis/Non-photochemical quenching"}],"tags":[],"updatedAt":"2025-11-21T18:05:14+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-29 09:05:23","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7613824","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7613824","identity":"rs-7613824","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}