title: OsWRKY28, a PAMP-responsive transrepressor, negatively regulates innate immune responses in rice against rice blast fungus.
abstract: WRKY transcription factors form a large family of plant-specific transcription factors and participate in plant defense responses either as positive or negative regulators. In this study, we comprehensively analyzed the role of one of the group IIa WRKY transcription factors in rice, OsWRKY28, in the regulation of basal defense responses to a compatible race of the rice blast fungus Magnaporthe oryzae, strain Ina86-137. The expression analyses of the group IIa WRKY transcription factors in rice revealed that OsWRKY28, together with OsWRKY71, exhibit an early-induced expression prior to the late-induced expressions of OsWRKY62 and OsWRKY76. The GFP-OsWRKY28 fusion protein localized mainly in the nuclei of onion epidermal cells, and the maltose-binding protein-fused OsWRKY28 recombinant protein specifically bound to W-box elements. A transient reporter gene assay clearly showed that OsWRKY28 functions as a transcriptional repressor. Overexpression of OsWRKY28 in rice plants resulted in enhanced susceptibility to Ina86-137. Finally, transcriptome analysis revealed that the induction of several defense-related genes in the wild type after Ina86-137 infection was counteracted in OsWRKY28-overexpressing rice plants. These results strongly suggest that OsWRKY28 is a negative regulator of basal defense responses against Ina86-137 and acts as a modulator to maintain the responses at an appropriate level by attenuating the activation of defense-related gene expression levels.
authors: Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
authors: Tetsuya
authors: T
authors: Chujo
authors: Koji
authors: K
authors: Miyamoto
authors: Takeo
authors: T
authors: Shimogawa
authors: Takafumi
authors: T
authors: Shimizu
authors: Yuko
authors: Y
authors: Otake
authors: Naoki
authors: N
authors: Yokotani
authors: Yoko
authors: Y
authors: Nishizawa
authors: Naoto
authors: N
authors: Shibuya
authors: Hideaki
authors: H
authors: Nojiri
authors: Hisakazu
authors: H
authors: Yamane
authors: Eiichi
authors: E
authors: Minami
authors: Kazunori
authors: K
authors: Okada
mesh_terms: D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D018744:DNA, Plant / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D020082:Magnaporthe / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D051192:Receptors, Pattern Recognition / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D051192:Receptors, Pattern Recognition; D012097:Repressor Proteins