The calcium transporter ANNEXIN1 mediates cold-induced calcium signaling and freezing tolerance in plants.

Qiangbo Liu, Yanglin Ding, Yiting Shi, Liang Ma, Yi Wang, Chunpeng Song, Katie A Wilkins, Julia M Davies, Heather Knight, Marc R Knight, Zhizhong Gong, Yan Guo, Shuhua Yang

OAI: oai:www.repository.cam.ac.uk:1810/315751 • DOI: 10.17863/CAM.62865

The transient elevation of cytosolic free calcium concentration ([Ca2+ ]cyt ) induced by cold stress is a well-established phenomenon; however, the underlying mechanism remains elusive. Here, we report that the Ca2+ -permeable transporter ANNEXIN1 (AtANN1) mediates cold-triggered Ca2+ influx and freezing tolerance in Arabidopsis thaliana. The loss of function of AtANN1 substantially impaired freezing tolerance, reducing the cold-induced [Ca2+ ]cyt increase and upregulation of the cold-responsive CBF and COR genes. Further analysis showed that the OST1/SnRK2.6 kinase interacted with and phosphorylated AtANN1, which consequently enhanced its Ca2+ transport activity, thereby potentiating Ca2+ signaling. Consistent with these results and freezing sensitivity of ost1 mutants, the cold-induced [Ca2+ ]cyt elevation in the ost1-3 mutant was reduced. Genetic analysis indicated that AtANN1 acts downstream of OST1 in responses to cold stress. Our data thus uncover a cascade linking OST1-AtANN1 to cold-induced Ca2+ signal generation, which activates the cold response and consequently enhances freezing tolerance in Arabidopsis.

Arabidopsis OST1 kinase calcium signal calcium-permeable transporter AtANN1 freezing tolerance Arabidopsis Arabidopsis Proteins Calcium Calcium Signaling Cell Membrane Cold Temperature Cold-Shock Response Freezing Gene Expression Regulation Plant Protein Kinases Transcription Factors