Release of SOS2 kinase from sequestration with GIGANTEA determines salt tolerance in Arabidopsis

Nat Commun. 2013:4:1352. doi: 10.1038/ncomms2357.

Abstract

Environmental challenges to plants typically entail retardation of vegetative growth and delay or cessation of flowering. Here we report a link between the flowering time regulator, GIGANTEA (GI), and adaptation to salt stress that is mechanistically based on GI degradation under saline conditions, thus retarding flowering. GI, a switch in photoperiodicity and circadian clock control, and the SNF1-related protein kinase SOS2 functionally interact. In the absence of stress, the GI:SOS2 complex prevents SOS2-based activation of SOS1, the major plant Na(+)/H(+)-antiporter mediating adaptation to salinity. GI overexpressing, rapidly flowering, plants show enhanced salt sensitivity, whereas gi mutants exhibit enhanced salt tolerance and delayed flowering. Salt-induced degradation of GI confers salt tolerance by the release of the SOS2 kinase. The GI-SOS2 interaction introduces a higher order regulatory circuit that can explain in molecular terms, the long observed connection between floral transition and adaptive environmental stress tolerance in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / drug effects
  • Arabidopsis / enzymology*
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / metabolism*
  • Flowers / physiology
  • Models, Biological
  • Phosphorylation / drug effects
  • Protein Binding / drug effects
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein Stability / drug effects
  • Proteolysis / drug effects
  • Salt Tolerance / drug effects
  • Salt Tolerance / physiology*
  • Signal Transduction / drug effects
  • Sodium Chloride / pharmacology
  • Sodium-Hydrogen Exchangers / metabolism
  • Stress, Physiological / drug effects
  • Time Factors

Substances

  • Arabidopsis Proteins
  • GI protein, Arabidopsis
  • SOS1 protein, Arabidopsis
  • SOS3 protein, Arabidopsis
  • Sodium-Hydrogen Exchangers
  • Sodium Chloride
  • SOS2 protein, Arabidopsis
  • Protein Serine-Threonine Kinases