The mitogen-activated protein kinase cascade MKK3-MPK6 is an important part of the jasmonate signal transduction pathway in Arabidopsis

Plant Cell. 2007 Mar;19(3):805-18. doi: 10.1105/tpc.106.046581. Epub 2007 Mar 16.

Abstract

The plant hormone jasmonic acid (JA) plays a key role in the environmental stress responses and developmental processes of plants. Although ATMYC2/JASMONATE-INSENSITIVE1 (JIN1) is a major positive regulator of JA-inducible gene expression and essential for JA-dependent developmental processes in Arabidopsis thaliana, molecular mechanisms underlying the control of ATMYC2/JIN1 expression remain largely unknown. Here, we identify a mitogen-activated protein kinase (MAPK) cascade, MAPK KINASE 3 (MKK3)-MAPK 6 (MPK6), which is activated by JA in Arabidopsis. We also show that JA negatively controls ATMYC2/JIN1 expression, based on quantitative RT-PCR and genetic analyses using gain-of-function and loss-of-function mutants of the MKK3-MPK6 cascade. These results indicate that this kinase unit plays a key role in JA-dependent negative regulation of ATMYC2/JIN1 expression. Both positive and negative regulation by JA may be used to fine-tune ATMYC2/JIN1 expression to control JA signaling. Moreover, JA-regulated root growth inhibition is affected by mutations in the MKK3-MPK6 cascade, which indicates important roles in JA signaling. We provide a model explaining how MPK6 can convert three distinct signals - JA, pathogen, and cold/salt stress - into three different sets of responses in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / drug effects*
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
  • Cyclopentanes / pharmacology*
  • Enzyme Activation / drug effects
  • Ethylenes / pharmacology
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant / drug effects
  • Genes, Plant
  • MAP Kinase Kinase 3 / metabolism*
  • Mitogen-Activated Protein Kinases / metabolism*
  • Models, Biological
  • Mutant Proteins / metabolism
  • Oxylipins
  • Plant Roots / drug effects
  • Plant Roots / enzymology
  • Plant Roots / growth & development
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Signal Transduction / drug effects*

Substances

  • Arabidopsis Proteins
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Cyclopentanes
  • Ethylenes
  • MYC2 protein, Arabidopsis
  • Mutant Proteins
  • Oxylipins
  • RNA, Messenger
  • jasmonic acid
  • ethylene
  • MPK6 protein, Arabidopsis
  • Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 3