2. Academic Validation
  3. Arabidopsis HSFA1b functions as a heat sensor inhibiting OST1-mediated stomatal closure through its adenylate-cyclase activity

Arabidopsis HSFA1b functions as a heat sensor inhibiting OST1-mediated stomatal closure through its adenylate-cyclase activity

  • Mol Plant. 2025 Sep 1;18(9):1549-1566. doi: 10.1016/j.molp.2025.07.018.
Yu Zhang 1,  Ru-Feng Song 2,  Xiao-Yu Hu 2,  Hui Zhou 2,  Wei Wang 2,  Junli Zhang 2,  Xin Zhang 2,  Liu-Mei Li 2,  Su-Ting Wang 2,  Yuwei Song 2,  Fuyou Xiang 2,  Jingjing Xing 2,  Yu Long 2,  Changqing Zhang 2,  José Ramón Botella 3,  Guoyong An 2,  Siyi Guo 4,  Wen-Cheng Liu 5,  Chun-Peng Song 6
Affiliations

Affiliations

  • 1 State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China; Sanya Institute, Henan University, Sanya 572025, China.
  • 2 State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China.
  • 3 Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
  • 4 State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China; Sanya Institute, Henan University, Sanya 572025, China. Electronic address: guosiyi@henu.edu.cn.
  • 5 State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China; Sanya Institute, Henan University, Sanya 572025, China. Electronic address: liuwencheng@henu.edu.cn.
  • 6 State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China; Sanya Institute, Henan University, Sanya 572025, China. Electronic address: songcp@henu.edu.cn.
PMID: 40745919 DOI: 10.1016/j.molp.2025.07.018
Abstract

Global warming profoundly affects plant communities, but the mechanisms and the identity of sensors controlling plant thermosensing remain poorly understood. In this study, we identify the heat-shock factor A1b (HSFA1b) transcription factor as a heat sensor that regulates stomatal responses by inhibiting open stomata 1 (OST1) kinase activity in Arabidopsis. OST1 induces stomatal closure under heat stress independently of Abscisic acid, and its activity is inhibited in the cytosol by the C-terminus of HSFA1b through intrinsic Adenylate Cyclase (AC) activity. Arabidopsis HSFA1b could complement an AC-deficient bacterium, and the cyclic AMP produced by HSFA1b could bind to and inhibit OST1 kinase activity. This inhibition is relieved under heat stress by HSFA1b translocation into the nucleus, coupling OST1 inhibition with the activation of heat-shock protein genes involved in the perception and signaling of high temperature. Collectively, our study demonstrates that HSFA1b functions as a heat sensor, inhibiting heat stress-induced and OST1-mediated stomatal closure through its AC activity.

Keywords

OST1; adenylate cyclase; cAMP; heat; stomata; transcription factor.

Figures
Products