title: Arabidopsis mitogen-activated protein kinase kinases MKK1 and MKK2 have overlapping functions in defense signaling mediated by MEKK1, MPK4, and MKS1.
abstract: 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.
authors.affiliation: Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark.
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Qiu
authors.forename: Lu
authors.initials: L
authors.lastname: Zhou
authors.forename: Byung-Wook
authors.initials: BW
authors.lastname: Yun
authors.forename: Henrik Bjørn
authors.initials: HB
authors.lastname: Nielsen
authors.forename: Berthe Katrine
authors.initials: BK
authors.lastname: Fiil
authors.forename: Klaus
authors.initials: K
authors.lastname: Petersen
authors.forename: Jim
authors.initials: J
authors.lastname: Mackinlay
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Loake
authors.forename: John
authors.initials: J
authors.lastname: Mundy
authors.forename: Peter C
authors.initials: PC
authors.lastname: Morris
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048728:MAP Kinase Kinase Kinase 1 / Q000378:metabolism; D020935:MAP Kinase Signaling System; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016254:Mutagenesis, Insertional; D009687:Nuclear Proteins; D054883:Oxylipins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology*; D010937:Plant Growth Regulators / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005030:Ethylenes; C503586:MKS1 protein, Arabidopsis; D009687:Nuclear Proteins; D054883:Oxylipins; D010750:Phosphoproteins; D010937:Plant Growth Regulators; C011006:jasmonic acid; C036216:ethylene; C436292:AtMPK4 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; D048369:MAP Kinase Kinase 1; C488959:MKK2 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases; D020156:Salicylic Acid