title: Phosphorylation of an ERF transcription factor by Arabidopsis MPK3/MPK6 regulates plant defense gene induction and fungal resistance.
abstract: Arabidopsis thaliana MPK3 and MPK6, two mitogen-activated protein kinases (MAPKs or MPKs), play critical roles in plant disease resistance by regulating multiple defense responses. Previously, we characterized the regulation of phytoalexin biosynthesis by Arabidopsis MPK3/MPK6 cascade and its downstream WRKY33 transcription factor. Here, we report another substrate of MPK3/MPK6, ETHYLENE RESPONSE FACTOR6 (ERF6), in regulating Arabidopsis defense gene expression and resistance to the necrotrophic fungal pathogen Botrytis cinerea. Phosphorylation of ERF6 by MPK3/MPK6 in either the gain-of-function transgenic plants or in response to B. cinerea infection increases ERF6 protein stability in vivo. Phospho-mimicking ERF6 is able to constitutively activate defense-related genes, especially those related to fungal resistance, including PDF1.1 and PDF1.2, and confers enhanced resistance to B. cinerea. By contrast, expression of ERF6-EAR, in which ERF6 was fused to the ERF-associated amphiphilic repression (EAR) motif, strongly suppresses B. cinerea-induced defense gene expression, leading to hypersusceptibility of the ERF6-EAR transgenic plants to B. cinerea. Different from ERF1, the regulation and function of ERF6 in defensin gene activation is independent of ethylene. Based on these data, we conclude that ERF6, another substrate of MPK3 and MPK6, plays important roles downstream of the MPK3/MPK6 cascade in regulating plant defense against fungal pathogens.
authors.affiliation: Division of Biochemistry, Interdisciplinary Plant Group, Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: Xiangzong
authors.initials: X
authors.lastname: Meng
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.forename: Yunxia
authors.initials: Y
authors.lastname: He
authors.forename: Kwang-Yeol
authors.initials: KY
authors.lastname: Yang
authors.forename: Breanne
authors.initials: B
authors.lastname: Mordorski
authors.forename: Yidong
authors.initials: Y
authors.lastname: Liu
authors.forename: Shuqun
authors.initials: S
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000276:immunology / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020171:Botrytis / Q000472:pathogenicity; D060467:Disease Resistance; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000382:microbiology; D055550:Protein Stability; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; C582825:ERF6 protein, Arabidopsis; D005030:Ethylenes; D014157:Transcription Factors; C036216:ethylene; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases