A circadian rheostat drives proton electrochemical gradients to optimize cell-type specific growth in Arabidopsis
Xiong, Lu (Centre de Recerca en Agrigenòmica)
Seki, Motohide (Kyushu University (Fukuoka, Japó))
Satake, Akiko (Kyushu University (Fukuoka, Japó))
Mas, Paloma (Centre de Recerca en Agrigenòmica)

Date:	2026
Abstract:	Plant growth relies on the activity of key transcription factors. Here, we uncover a mechanism for organ-specific growth driven by opposing electrochemical signals that propagate in a cell-type-specific manner. Using a genetically encoded pH sensor and a pH-sensitive dye, we show that apoplastic pH in epidermal cells oscillates antiphasically relative to phloem pH. The clock component CCA1 lowers apoplastic pH in hypocotyl epidermal cells while increasing it in companion cells. This opposing regulation promotes hypocotyl growth but inhibits root elongation. Mechanistically, CCA1 activates auxin signaling in shoots while repressing sucrose transporter 2 and the electrogenic (H+)-pump ATPase AHA3 by directly binding their promoters. The repression decreases sucrose loading into the phloem and slows transport velocity. Expressing CCA1 in the phloem is sufficient to inhibit root elongation, whereas AHA3 overexpression in CCA1 overexpressing seedlings rescues root growth. Thus, a circadian rheostat orchestrates electrochemical signals to optimize source capacity with sink demand.
Grants:	Agencia Estatal de Investigación PID2022-137770NB-I00 Generalitat de Catalunya 2021/SGR-01131 Ministerio de Economía y Competitividad SEV-2015-0533 Ministerio de Ciencia e Innovación CEX2019-000902-S
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Cell-type-specific growth ; Circadian clock ; Proton pump ATPases ; Electrochemical signals ; Sucrose transport ; Source-sink balance ; CCA1 ; Arabidopsis thaliana
Published in:	Cell, Vol. 189 (February 2026) , ISSN 1097-4172

DOI: 10.1016/j.cell.2025.12.056

31 p, 7.4 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CRAG (Centre for Research in Agricultural Genomics)
Articles > Research articles
Articles > Published articles