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Article

  • The EMBO Journal (2008) 27, 2214 - 2221
  • doi:10.1038/emboj.2008.147

Published online: 24 July 2008

Arabidopsis MAP kinase 4 regulates gene expression through transcription factor release in the nucleus

Jin-Long Qiu1,a, Berthe Katrine Fiil1,a, Klaus Petersen1, Henrik Bjørn Nielsen2, Christopher J Botanga3, Stephan Thorgrimsen1, Kristoffer Palma1, Maria Cristina Suarez-Rodriguez1, Signe Sandbech-Clausen1, Jacek Lichota4, Peter Brodersen5, Klaus D Grasser4, Ole Mattsson1, Jane Glazebrook3, John Mundy1 and Morten Petersen1

  1. Department of Biology, University of Copenhagen, Copenhagen, Denmark
  2. Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
  3. Department of Plant Biology and Center for Microbial and Plant Genomics, University of Minnesota, St Paul, MN, USA
  4. Department of Life Sciences, Aalborg University, Aalborg, Denmark
  5. Institut de Biologie Moléculaire des Plantes du CNRS, Unité Propre de Recherche 2357, 12 rue du Général Zimmer, Strasbourg Cedex, France

Correspondence to:

Morten Petersen, Department of Biology, University of Copenhagen, Ole Maaloees Vej 5, Copenhagen 2200, Denmark. Tel.: +45 35322127; Fax: +45 35322128; E-mail: shutko@bio.ku.dk

aThese authors contributed equally to this work

Received 4 March 2008; Accepted 4 July 2008

Plant and animal perception of microbes through pathogen surveillance proteins leads to MAP kinase signalling and the expression of defence genes. However, little is known about how plant MAP kinases regulate specific gene expression. We report that, in the absence of pathogens, Arabidopsis MAP kinase 4 (MPK4) exists in nuclear complexes with the WRKY33 transcription factor. This complex depends on the MPK4 substrate MKS1. Challenge with Pseudomonas syringae or flagellin leads to the activation of MPK4 and phosphorylation of MKS1. Subsequently, complexes with MKS1 and WRKY33 are released from MPK4, and WRKY33 targets the promoter of PHYTOALEXIN DEFICIENT3 (PAD3) encoding an enzyme required for the synthesis of antimicrobial camalexin. Hence, wrky33 mutants are impaired in the accumulation of PAD3 mRNA and camalexin production upon infection. That WRKY33 is an effector of MPK4 is further supported by the suppression of PAD3 expression in mpk4–wrky33 double mutant backgrounds. Our data establish direct links between MPK4 and innate immunity and provide an example of how a plant MAP kinase can regulate gene expression by releasing transcription factors in the nucleus upon activation.

  • Keywords:

    • Arabidopsis,
    • defence response,
    • MAP kinase,
    • target genes,
    • transcription factor