---
OA_place: repository
OA_type: green
_id: '23175'
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.
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
author:
- first_name: Huifang
full_name: Song, Huifang
last_name: Song
- first_name: Angel
full_name: Baudon, Angel
last_name: Baudon
- first_name: Matthias
full_name: Freund, Matthias
last_name: Freund
- first_name: Marek
full_name: Randuch, Marek
id: 6ac4636d-15b2-11ec-abd3-fb8df79972ae
last_name: Randuch
- first_name: Aleš
full_name: Pěnčík, Aleš
last_name: Pěnčík
- first_name: Novák
full_name: Ondřej, Novák
last_name: Ondřej
- first_name: Zhaohui
full_name: He, Zhaohui
last_name: He
- first_name: Kerstin
full_name: Kaufmann, Kerstin
last_name: Kaufmann
- first_name: 'Nan'
full_name: Li, Nan
last_name: Li
- first_name: Matthew
full_name: Gilliham, Matthew
last_name: Gilliham
- first_name: Jiří
full_name: Friml, Jiří
id: 4159519E-F248-11E8-B48F-1D18A9856A87
last_name: Friml
orcid: 0000-0002-8302-7596
- first_name: Rainer
full_name: Hedrich, Rainer
last_name: Hedrich
- first_name: Shouguang
full_name: Huang, Shouguang
last_name: Huang
biorxivid: 1
citation:
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
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
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.
ieee: H. Song et al., “Ca2+ signature gates early auxin signaling in Arabidopsis
roots,” bioRxiv. .
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.
mla: Song, Huifang, 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.).
corr_author: '1'
date_created: 2026-10-19T11:51:47Z
date_published: 2026-08-26T00:00:00Z
date_updated: 2026-10-22T09:15:44Z
day: '26'
department:
- _id: JiFr
doi: 10.1101/2025.10.04.680446
external_id:
biorxivid:
- 10.1101/2025.10.04.680446
fulldoi: https://doi.org/10.1101/2025.10.04.680446
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1101/2025.10.04.680446
month: '08'
oa: 1
oa_version: Preprint
project:
- _id: 8f347782-16d5-11f0-9cad-8c19706ee739
grant_number: '101142681'
name: Cyclic nucleotides as second messengers in plants
- _id: 7bcece63-9f16-11ee-852c-ae94e099eeb6
grant_number: P37051
name: Guanylate cyclase activity of TIR1/AFBs auxin receptors
publication: bioRxiv
publication_status: draft
related_material:
record:
- id: '23145'
relation: dissertation_contains
status: public
status: public
title: Ca2+ signature gates early auxin signaling in Arabidopsis roots
tmp:
image: /images/cc_by_nc_nd.png
legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
(CC BY-NC-ND 4.0)
short: CC BY-NC-ND (4.0)
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...