STRESS INDUCED FACTOR 2 Regulates Arabidopsis Stomatal Immunity through Phosphorylation of the Anion Channel SLAC1

Plant Cell. 2020 Jul;32(7):2216-2236. doi: 10.1105/tpc.19.00578. Epub 2020 Apr 23.

Abstract

Upon recognition of microbes, pattern recognition receptors (PRRs) activate pattern-triggered immunity. FLAGELLIN SENSING2 (FLS2) and BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) form a typical PRR complex that senses bacteria. Here, we report that the kinase activity of the malectin-like receptor-like kinase STRESS INDUCED FACTOR 2 (SIF2) is critical for Arabidopsis (Arabidopsis thaliana) resistance to bacteria by regulating stomatal immunity. SIF2 physically associates with the FLS2-BAK1 PRR complex and interacts with and phosphorylates the guard cell SLOW ANION CHANNEL1 (SLAC1), which is necessary for abscisic acid (ABA)-mediated stomatal closure. SIF2 is also required for the activation of ABA-induced S-type anion currents in Arabidopsis protoplasts, and SIF2 is sufficient to activate SLAC1 anion channels in Xenopus oocytes. SIF2-mediated activation of SLAC1 depends on specific phosphorylation of Ser 65. This work reveals that SIF2 functions between the FLS2-BAK1 initial immunity receptor complex and the final actuator SLAC1 in stomatal immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism
  • Abscisic Acid / pharmacology
  • Animals
  • Arabidopsis / microbiology
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / immunology
  • Arabidopsis Proteins / metabolism*
  • Disease Resistance / physiology
  • Female
  • Histone Deacetylases / genetics
  • Histone Deacetylases / immunology
  • Histone Deacetylases / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / immunology
  • Membrane Proteins / metabolism*
  • Mutation
  • Oocytes / physiology
  • Phosphorylation
  • Plant Diseases / immunology
  • Plant Diseases / microbiology
  • Plant Immunity / drug effects
  • Plant Stomata / immunology*
  • Plant Stomata / metabolism
  • Plants, Genetically Modified
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / immunology
  • Repressor Proteins / metabolism*
  • Serine / metabolism
  • Xenopus

Substances

  • Arabidopsis Proteins
  • Membrane Proteins
  • Repressor Proteins
  • SLAC1 protein, Arabidopsis
  • Serine
  • Abscisic Acid
  • Protein Kinases
  • BAK1 protein, Arabidopsis
  • FLS2 protein, Arabidopsis
  • OST1 protein, Arabidopsis
  • Protein-Serine-Threonine Kinases
  • Histone Deacetylases
  • SIF2 protein, Arabidopsis