Mitogen-Activated Protein Kinase Cascade MKK3-MPK6 Is an Important Part of the Jasmonate Signal Transduction Pathway in Arabidopsis

• Published in: The Plant cell Vol. 19; no. 3; pp. 805 - 818
• Main Authors: Takahashi, Fuminori, Yoshida, Riichiro, Ichimura, Kazuya, Mizoguchi, Tsuyoshi, Seo, Shigemi, Yonezawa, Masahiro, Maruyama, Kyonoshin, Yamaguchi-Shinozaki, Kazuko, Shinozaki, Kazuo
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.03.2007
• Subjects: 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; Environmental stress; Enzyme Activation - drug effects; Ethylenes - pharmacology; Gene expression; Gene Expression Profiling; Gene expression regulation; Gene Expression Regulation, Plant - drug effects; Genes, Plant; MAP Kinase Kinase 3 - metabolism; Mitogen-Activated Protein Kinases - metabolism; Models, Biological; Mutant Proteins - metabolism; Oxylipins; Phenotypes; Plant cells; Plant growth; Plant Roots - drug effects; Plant Roots - enzymology; Plant Roots - growth & development; Plants; Proteins; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; Root growth; Seedlings; Signal Transduction - drug effects; Transgenic plants
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.106.046581

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: