{"OA_type":"green","status":"public","publication":"bioRxiv","year":"2026","author":[{"full_name":"Song, Huifang","first_name":"Huifang","last_name":"Song"},{"last_name":"Baudon","full_name":"Baudon, Angel","first_name":"Angel"},{"full_name":"Freund, Matthias","first_name":"Matthias","last_name":"Freund"},{"id":"6ac4636d-15b2-11ec-abd3-fb8df79972ae","first_name":"Marek","full_name":"Randuch, Marek","last_name":"Randuch"},{"last_name":"Pěnčík","first_name":"Aleš","full_name":"Pěnčík, Aleš"},{"last_name":"Ondřej","first_name":"Novák","full_name":"Ondřej, Novák"},{"last_name":"He","first_name":"Zhaohui","full_name":"He, Zhaohui"},{"last_name":"Kaufmann","full_name":"Kaufmann, Kerstin","first_name":"Kerstin"},{"last_name":"Li","full_name":"Li, Nan","first_name":"Nan"},{"first_name":"Matthew","full_name":"Gilliham, Matthew","last_name":"Gilliham"},{"orcid":"0000-0002-8302-7596","id":"4159519E-F248-11E8-B48F-1D18A9856A87","first_name":"Jiří","full_name":"Friml, Jiří","last_name":"Friml"},{"last_name":"Hedrich","full_name":"Hedrich, Rainer","first_name":"Rainer"},{"full_name":"Huang, Shouguang","first_name":"Shouguang","last_name":"Huang"}],"oa":1,"corr_author":"1","tmp":{"name":"Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)","short":"CC BY-NC-ND (4.0)","legal_code_url":"https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode","image":"/images/cc_by_nc_nd.png"},"abstract":[{"lang":"eng","text":"Plants must continually balance growth with arrest, especially under stress. Auxin signaling acts as a central regulatory hub in this process, yet the mechanisms that dynamically tune early auxin signalling in real time remain unknown. Here, we used the light-gated, Ca2+-permeable Channelrhodopsin 2 variant XXM2.0 to optogenetically impose defined Ca2+ signatures on Arabidopsis root cells. Repetitive light activation triggered cytosolic Ca2+ signals that in turn suppressed auxin-induced membrane depolarization and Ca2+ transients. Moreover, prolonged optogenetic Ca2+ stimulation affects auxin-responsive transcriptional reprogramming. As phenotypic output, reversible inhibition of root growth by suppressing cell division and elongation was observed. We further identify a candidate CaM7–CNGC14 module that likely mediates Ca2+-dependent gating of early auxin signalling. Our study thus introduces a synthetic biology approach to decompose calcium–auxin crosstalk in plant cells, and demonstrates that optogenetically imposed cytosolic Ca2+ signals act as dynamic regulators of auxin susceptibility in roots."}],"date_published":"2026-08-26T00:00:00Z","month":"08","OA_place":"repository","biorxivid":1,"date_updated":"2026-10-22T09:15:44Z","department":[{"_id":"JiFr"}],"date_created":"2026-10-19T11:51:47Z","acknowledgement":"We would like to thank Dirk Becker (University of Wuerzburg) for his help in making the optogenetic constructs and for his comments on the manuscript. We also appreciate Rob Roelfsema (University of Wuerzburg) for his feedback on the manuscript. We sincerely thank the anonymous reviewers for the thoughtful and inspiring suggestions that helped broaden the discussion and identify important future research directions. Funding\r\nNational Key R&D Program of China, 2025YFA0923400 (RH)\r\n\r\nNational Natural Science Foundation of China (NSFC), W2531024 (RH); 32271501(NL)\r\n\r\nNSFC-Excellent Young Scientists Fund Program (overseas) (SH)\r\n\r\nNSFC-RFIS, ZB2025101410702 (RH)\r\n\r\nGuangdong Pearl River Talents Program, 2023ZT10N033\r\n\r\nChina Scholarship Council no. 202306510063 (HS)\r\n\r\nThe European Research Council grant 101142681 CYNIPS (JF)\r\n\r\nAustrian Science Fund grant FWF; P 37051-B (JF)\r\n\r\nGerman Research Foundation grant CRC 1644 (512328399; 512328399) (KK, ZH)\r\n\r\nERC Synergy project STARMORPH, reg. no. 101166880 (AP, ON)","article_processing_charge":"No","language":[{"iso":"eng"}],"fulldoi":"https://doi.org/10.1101/2025.10.04.680446","oa_version":"Preprint","_id":"23175","day":"26","doi":"10.1101/2025.10.04.680446","related_material":{"record":[{"id":"23145","status":"public","relation":"dissertation_contains"}]},"project":[{"name":"Cyclic nucleotides as second messengers in plants","grant_number":"101142681","_id":"8f347782-16d5-11f0-9cad-8c19706ee739"},{"name":"Guanylate cyclase activity of TIR1/AFBs auxin receptors","grant_number":"P37051","_id":"7bcece63-9f16-11ee-852c-ae94e099eeb6"}],"type":"preprint","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","title":"Ca2+ signature gates early auxin signaling in Arabidopsis roots","publication_status":"draft","external_id":{"biorxivid":["10.1101/2025.10.04.680446"]},"main_file_link":[{"open_access":"1","url":"https://doi.org/10.1101/2025.10.04.680446"}],"citation":{"chicago":"Song, Huifang, Angel Baudon, Matthias Freund, Marek Randuch, Aleš Pěnčík, Novák Ondřej, Zhaohui He, et al. “Ca2+ Signature Gates Early Auxin Signaling in Arabidopsis Roots.” BioRxiv, n.d. https://doi.org/10.1101/2025.10.04.680446.","ista":"Song H, Baudon A, Freund M, Randuch M, Pěnčík A, Ondřej N, He Z, Kaufmann K, Li N, Gilliham M, Friml J, Hedrich R, Huang S. Ca2+ signature gates early auxin signaling in Arabidopsis roots. bioRxiv, 10.1101/2025.10.04.680446.","apa":"Song, H., Baudon, A., Freund, M., Randuch, M., Pěnčík, A., Ondřej, N., … Huang, S. (n.d.). Ca2+ signature gates early auxin signaling in Arabidopsis roots. bioRxiv. https://doi.org/10.1101/2025.10.04.680446","ama":"Song H, Baudon A, Freund M, et al. Ca2+ signature gates early auxin signaling in Arabidopsis roots. bioRxiv. doi:10.1101/2025.10.04.680446","short":"H. Song, A. Baudon, M. Freund, M. Randuch, A. Pěnčík, N. Ondřej, Z. He, K. Kaufmann, N. Li, M. Gilliham, J. Friml, R. Hedrich, S. Huang, BioRxiv (n.d.).","mla":"Song, Huifang, et al. “Ca2+ Signature Gates Early Auxin Signaling in Arabidopsis Roots.” BioRxiv, doi:10.1101/2025.10.04.680446.","ieee":"H. Song et al., “Ca2+ signature gates early auxin signaling in Arabidopsis roots,” bioRxiv. ."}}