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

作者：Qiu Jin Long; Fiil Berthe Katrine; Petersen Klaus; Nielsen Henrik Bjorn; Botanga Christopher J; Thorgrimsen Stephan; Palma Kristoffer; Suarez Rodriguez Maria Cristina; Sandbech Clausen Signe; Lichota Jacek; Brodersen Peter; Grasser Klaus D; Mattsson Ole; Glazebrook Jane; Mundy John; Petersen Morten^*

来源：The EMBO Journal, 2008, 27(16): 2214-2221.

DOI：10.1038/emboj.2008.147

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

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.

• 出版日期2008-8-20