Arabidopsis CALCIUM-DEPENDENT PROTEIN KINASE8 and CATALASE3 Function in Abscisic Acid-Mediated Signaling and H2O2 Homeostasis in Stomatal Guard Cells under Drought Stress

Plant Cell. 2015 May;27(5):1445-60. doi: 10.1105/tpc.15.00144. Epub 2015 May 12.

Abstract

Drought is a major threat to plant growth and crop productivity. Calcium-dependent protein kinases (CDPKs, CPKs) are believed to play important roles in plant responses to drought stress. Here, we report that Arabidopsis thaliana CPK8 functions in abscisic acid (ABA)- and Ca(2+)-mediated plant responses to drought stress. The cpk8 mutant was more sensitive to drought stress than wild-type plants, while the transgenic plants overexpressing CPK8 showed enhanced tolerance to drought stress compared with wild-type plants. ABA-, H2O2-, and Ca(2+)-induced stomatal closing were impaired in cpk8 mutants. Arabidopsis CATALASE3 (CAT3) was identified as a CPK8-interacting protein, confirmed by yeast two-hybrid, coimmunoprecipitation, and bimolecular fluorescence complementation assays. CPK8 can phosphorylate CAT3 at Ser-261 and regulate its activity. Both cpk8 and cat3 plants showed lower catalase activity and higher accumulation of H2O2 compared with wild-type plants. The cat3 mutant displayed a similar drought stress-sensitive phenotype as cpk8 mutant. Moreover, ABA and Ca(2+) inhibition of inward K(+) currents were diminished in guard cells of cpk8 and cat3 mutants. Together, these results demonstrated that CPK8 functions in ABA-mediated stomatal regulation in responses to drought stress through regulation of CAT3 activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism*
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Calcium / metabolism*
  • Catalase / genetics
  • Catalase / metabolism
  • Cyclin-Dependent Kinase 8 / genetics
  • Cyclin-Dependent Kinase 8 / metabolism*
  • Droughts
  • Gene Expression Regulation, Plant
  • Homeostasis
  • Hydrogen Peroxide / metabolism*
  • Plant Growth Regulators / metabolism*
  • Plant Stomata / enzymology
  • Plant Stomata / genetics
  • Plant Stomata / physiology
  • Plants, Genetically Modified
  • Protein Kinases / genetics
  • Protein Kinases / metabolism
  • Signal Transduction*
  • Stress, Physiological

Substances

  • Arabidopsis Proteins
  • Plant Growth Regulators
  • Abscisic Acid
  • Hydrogen Peroxide
  • CAT3 protein, Arabidopsis
  • Catalase
  • Protein Kinases
  • calcium-dependent protein kinase
  • CDK8 protein, Arabidopsis
  • Cyclin-Dependent Kinase 8
  • Calcium