title: WRKY Transcription Factors Phosphorylated by MAPK Regulate a Plant Immune NADPH Oxidase in Nicotiana benthamiana.
abstract: Pathogen attack sequentially confers pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) after sensing of pathogen patterns and effectors by plant immune receptors, respectively. Reactive oxygen species (ROS) play pivotal roles in PTI and ETI as signaling molecules. Nicotiana benthamiana RBOHB, an NADPH oxidase, is responsible for both the transient PTI ROS burst and the robust ETI ROS burst. Here, we show that RBOHB transactivation mediated by MAPK contributes to R3a/AVR3a-triggered ETI (AVR3a-ETI) ROS burst. RBOHB is markedly induced during the ETI and INF1-triggered PTI (INF1-PTI), but not flg22-tiggered PTI (flg22-PTI). We found that the RBOHB promoter contains a functional W-box in the R3a/AVR3a and INF1 signal-responsive cis-element. Ectopic expression of four phospho-mimicking mutants of WRKY transcription factors, which are MAPK substrates, induced RBOHB, and yeast one-hybrid analysis indicated that these mutants bind to the cis-element. Chromatin immunoprecipitation assays indicated direct binding of the WRKY to the cis-element in plants. Silencing of multiple WRKY genes compromised the upregulation of RBOHB, resulting in impairment of AVR3a-ETI and INF1-PTI ROS bursts, but not the flg22-PTI ROS burst. These results suggest that the MAPK-WRKY pathway is required for AVR3a-ETI and INF1-PTI ROS bursts by activation of RBOHB.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Adachi
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Nakano
authors.affiliation: ZEN-NOH, Hiratsuka 254-0016, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Miyagawa
authors.affiliation: RIKEN CSRS, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Ishihama
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Yoshioka
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Katou
authors.affiliation: Faculty of Agriculture, Ehime University, Matsuyama 790-8566, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yaeno
authors.affiliation: RIKEN CSRS, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Ken
authors.identifier: http://orcid.org/0000-0002-0349-3870
authors.initials: K
authors.lastname: Shirasu
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan hyoshiok@agr.nagoya-u.ac.jp.
authors.forename: Hirofumi
authors.identifier: http://orcid.org/0000-0003-3956-7250
authors.initials: H
authors.lastname: Yoshioka
mesh_terms: D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions / Q000276:immunology; D020935:MAP Kinase Signaling System; D008969:Molecular Sequence Data; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D055750:Phytophthora infestans / Q000472:pathogenicity; D057865:Plant Immunity; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D017382:Reactive Oxygen Species / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D011198:Solanum tuberosum / Q000235:genetics; D014026:Nicotiana / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D019255:NADPH Oxidases