MAPK phosphatase MKP2 mediates disease responses in Arabidopsis and functionally interacts with MPK3 and MPK6

Plant J. 2010 Sep;63(6):1017-30. doi: 10.1111/j.1365-313X.2010.04297.x.

Abstract

Mitogen-activated protein kinase (MAPK) cascades have important functions in plant stress responses and development and are key players in reactive oxygen species (ROS) signalling and in innate immunity. In Arabidopsis, the transmission of ROS and pathogen signalling by MAPKs involves the coordinated activation of MPK6 and MPK3; however, the specificity of their negative regulation by phosphatases is not fully known. Here, we present genetic analyses showing that MAPK phosphatase 2 (MKP2) regulates oxidative stress and pathogen defence responses and functionally interacts with MPK3 and MPK6. We show that plants lacking a functional MKP2 gene exhibit delayed wilting symptoms in response to Ralstonia solanacearum and, by contrast, acceleration of disease progression during Botrytis cinerea infection, suggesting that this phosphatase plays differential functions in biotrophic versus necrotrophic pathogen-induced responses. MKP2 function appears to be linked to MPK3 and MPK6 regulation, as indicated by BiFC experiments showing that MKP2 associates with MPK3 and MPK6 in vivo and that in response to fungal elicitors MKP2 exerts differential affinity versus both kinases. We also found that MKP2 interacts with MPK6 in HR-like responses triggered by fungal elicitors, suggesting that MPK3 and MPK6 are subject to differential regulation by MKP2 in this process. We propose that MKP2 is a key regulator of MPK3 and MPK6 networks controlling both abiotic and specific pathogen responses in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis / microbiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Botrytis / pathogenicity
  • Immunoprecipitation
  • Microscopy, Confocal
  • Mitogen-Activated Protein Kinase Kinases / genetics
  • Mitogen-Activated Protein Kinase Kinases / metabolism*
  • Mitogen-Activated Protein Kinase Phosphatases / genetics
  • Mitogen-Activated Protein Kinase Phosphatases / metabolism*
  • Mitogen-Activated Protein Kinases / genetics
  • Mitogen-Activated Protein Kinases / metabolism*
  • Oxidative Stress / genetics
  • Oxidative Stress / physiology
  • Plants, Genetically Modified / enzymology*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism*
  • Plants, Genetically Modified / microbiology
  • Polymerase Chain Reaction
  • Ralstonia solanacearum / pathogenicity

Substances

  • Arabidopsis Proteins
  • AtMPK3 protein, Arabidopsis
  • MPK6 protein, Arabidopsis
  • Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinase Kinases
  • Mitogen-Activated Protein Kinase Phosphatases