Journal Article

Arabidopsis Mitogen-Activated Protein Kinase Kinases MKK1 and MKK2 Have Overlapping Functions in Defense Signaling Mediated by MEKK1, MPK4, and MKS1

Zhou, Lu, MacKinlay, Jim, Morris, Peter C., Fiil, Berthe Katrine, Petersen, Klaus, Yun, Byung-Wook, Qiu, Jin-Long, Loake, Gary J., Nielsen, Henrik Bjørn, Mundy, John

2008

Overview

The Arabidopsis (Arabidopsis thaliana) MKK1 and MKK2 mitogen-activated protein kinase kinases have been implicated in biotic and abiotic stress responses as part of a signaling cascade including MEKK1 and MPK4. Here, the double loss-of-function mutant (mkk1/2) of MKK1 and MKK2 is shown to have marked phenotypes in development and disease resistance similar to those of the single mekk1 and mpk4 mutants. Because mkk1 or mkk2 single mutants appear wild type, basal levels of MPK4 activity are not impaired in them, and MKK1 and MKK2 are in part functionally redundant in unchallenged plants. These findings are confirmed and extended by biochemical and molecular analyses implicating the kinases in jasmonate- and salicylate-dependent defense responses, mediated in part via the MPK4 substrate MKS1. In addition, transcriptome analyses delineate overlapping and specific effects of the kinases on global gene expression patterns demonstrating both redundant and unique functions for MKK1 and MKK2.

• Publisher: American Society of Plant Biologists,American Society of Plant Physiologists
• Subject: Arabidopsis / Arabidopsis - enzymology / Arabidopsis - genetics / Arabidopsis - immunology / Arabidopsis Proteins / Arabidopsis Proteins - genetics / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Biological and medical sciences / biotic stress / Cell Biology and Signal Transduction / Cyclopentanes / Cyclopentanes - metabolism / Disease resistance / enzymology / Ethylenes / Ethylenes - metabolism / Fundamental and applied biological sciences. Psychology / Gene expression / Gene expression regulation / genetics / immunology / MAP Kinase Kinase 1 / MAP Kinase Kinase 1 - genetics / MAP Kinase Kinase 1 - metabolism / MAP Kinase Kinase Kinase 1 / MAP Kinase Kinase Kinase 1 - metabolism / MAP Kinase Signaling System / metabolism / mitogen-activated protein kinase / Mitogen-Activated Protein Kinase Kinases / Mitogen-Activated Protein Kinase Kinases - genetics / Mitogen-Activated Protein Kinase Kinases - metabolism / Mitogen-Activated Protein Kinases / Mitogen-Activated Protein Kinases - metabolism / Mutagenesis, Insertional / mutants / Nuclear Proteins / Oxylipins / Oxylipins - metabolism / Pathogens / phenotype / Phenotypes / Phosphoproteins / Phosphoproteins - metabolism / Plant cells / Plant Diseases / Plant Diseases - immunology / Plant Growth Regulators / Plant Growth Regulators - metabolism / Plant morphology / Plant physiology and development / Plants / Reverse transcriptase polymerase chain reaction / RNA / Salicylic Acid / Salicylic Acid - metabolism / Signatures / stress response / transcriptome