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

EMBO J. 2021 Jan 15;40(2):e104559. doi: 10.15252/embj.2020104559. Epub 2020 Dec 29.


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.

Keywords: Arabidopsis; OST1 kinase; calcium signal; calcium-permeable transporter AtANN1; freezing tolerance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Calcium / metabolism*
  • Calcium Signaling / physiology*
  • Cell Membrane / metabolism
  • Cold Temperature
  • Cold-Shock Response / physiology*
  • Freezing
  • Gene Expression Regulation, Plant / physiology
  • Protein Kinases / metabolism
  • Transcription Factors / metabolism


  • Arabidopsis Proteins
  • Transcription Factors
  • Protein Kinases
  • Calcium