title: Induced Genome-Wide Binding of Three Arabidopsis WRKY Transcription Factors during Early MAMP-Triggered Immunity.
abstract: During microbial-associated molecular pattern-triggered immunity (MTI), molecules derived from microbes are perceived by cell surface receptors and upon signaling to the nucleus initiate a massive transcriptional reprogramming critical to mount an appropriate host defense response. WRKY transcription factors play an important role in regulating these transcriptional processes. Here, we determined on a genome-wide scale the flg22-induced in vivo DNA binding dynamics of three of the most prominent WRKY factors, WRKY18, WRKY40, and WRKY33. The three WRKY factors each bound to more than 1000 gene loci predominantly at W-box elements, the known WRKY binding motif. Binding occurred mainly in the 500-bp promoter regions of these genes. Many of the targeted genes are involved in signal perception and transduction not only during MTI but also upon damage-associated molecular pattern-triggered immunity, providing a mechanistic link between these functionally interconnected basal defense pathways. Among the additional targets were genes involved in the production of indolic secondary metabolites and in modulating distinct plant hormone pathways. Importantly, among the targeted genes were numerous transcription factors, encoding predominantly ethylene response factors, active during early MTI, and WRKY factors, supporting the previously hypothesized existence of a WRKY subregulatory network. Transcriptional analysis revealed that WRKY18 and WRKY40 function redundantly as negative regulators of flg22-induced genes often to prevent exaggerated defense responses.
authors.affiliation: Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, 50829 Koeln, Germany.
authors.forename: Rainer P
authors.initials: RP
authors.lastname: Birkenbihl
authors.affiliation: Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, 50829 Koeln, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kracher
authors.forename: Mario
authors.initials: M
authors.lastname: Roccaro
authors.affiliation: Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, 50829 Koeln, Germany somssich@mpipz.mpg.de.
authors.forename: Imre E
authors.identifier: 0000-0003-3066-5794
authors.initials: IE
authors.lastname: Somssich
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D005408:Flagellin / Q000494:pharmacology; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D063990:Gene Ontology; D018745:Genome, Plant / Q000235:genetics*; D015151:Immunoblotting; D009154:Mutation; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D057865:Plant Immunity / Q000187:drug effects / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D014157:Transcription Factors; C464509:WRKY18 protein, Arabidopsis; C517860:WRKY33 protein, Arabidopsis; C512070:WRKY40 protein, Arabidopsis; D005408:Flagellin