The Arabidopsis thaliana SOS2 gene encodes a protein kinase that is required for salt tolerance

Proc Natl Acad Sci U S A. 2000 Mar 28;97(7):3730-4. doi: 10.1073/pnas.97.7.3730.

Abstract

In Arabidopsis thaliana, the Salt Overly Sensitive 2 (SOS2) gene is required for intracellular Na(+) and K(+) homeostasis. Mutations in SOS2 cause Na(+) and K(+) imbalance and render plants more sensitive toward growth inhibition by high Na(+) and low K(+) environments. We isolated the SOS2 gene through positional cloning. SOS2 is predicted to encode a serine/threonine type protein kinase with an N-terminal catalytic domain similar to that of the yeast SNF1 kinase. Sequence analyses of sos2 mutant alleles reveal that both the N-terminal catalytic domain and the C-terminal regulatory domain of SOS2 are functionally essential. The steady-state level of SOS2 transcript is up-regulated by salt stress in the root. Autophosphorylation assays show that SOS2 is an active protein kinase. In the recessive sos2-5 allele, a conserved glycine residue in the kinase catalytic domain is changed to glutamate. This mutation abolishes SOS2 autophosphorylation, indicating that SOS2 protein kinase activity is required for salt tolerance.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptation, Physiological / genetics*
  • Amino Acid Sequence
  • Arabidopsis / enzymology
  • Arabidopsis / genetics*
  • Arabidopsis / physiology
  • Arabidopsis Proteins
  • Base Sequence
  • Cloning, Molecular
  • DNA, Plant
  • Molecular Sequence Data
  • Osmolar Concentration
  • Plant Roots / enzymology
  • Protein Serine-Threonine Kinases / genetics*
  • Salts*
  • Sequence Homology, Amino Acid
  • Up-Regulation

Substances

  • Arabidopsis Proteins
  • DNA, Plant
  • Salts
  • SOS2 protein, Arabidopsis
  • Protein Serine-Threonine Kinases

Associated data

  • GENBANK/AF237670