title: Negative regulation of ABA signaling by WRKY33 is critical for Arabidopsis immunity towards Botrytis cinerea 2100.
abstract: The Arabidopsis mutant wrky33 is highly susceptible to Botrytis cinerea. We identified &gt;1680 Botrytis-induced WRKY33 binding sites associated with 1576 Arabidopsis genes. Transcriptional profiling defined 318 functional direct target genes at 14 hr post inoculation. Comparative analyses revealed that WRKY33 possesses dual functionality acting either as a repressor or as an activator in a promoter-context dependent manner. We confirmed known WRKY33 targets involved in hormone signaling and phytoalexin biosynthesis, but also uncovered a novel negative role of abscisic acid (ABA) in resistance towards B. cinerea 2100. The ABA biosynthesis genes NCED3 and NCED5 were identified as direct targets required for WRKY33-mediated resistance. Loss-of-WRKY33 function resulted in elevated ABA levels and genetic studies confirmed that WRKY33 acts upstream of NCED3/NCED5 to negatively regulate ABA biosynthesis. This study provides the first detailed view of the genome-wide contribution of a specific plant transcription factor in modulating the transcriptional network associated with plant immunity.
authors.affiliation: Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Köln, Germany.
authors.forename: Shouan
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Köln, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kracher
authors.affiliation: Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Halle, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Ziegler
authors.affiliation: Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Köln, 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, Köln, Germany.
authors.forename: Imre E
authors.initials: IE
authors.lastname: Somssich
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis*; D017360:Arabidopsis / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins; D053898:Biosynthetic Pathways; D020171:Botrytis / Q000254:growth & development* / Q000276:immunology; D049308:Dioxygenases / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010940:Plant Proteins / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; D014157:Transcription Factors; C517860:WRKY33 protein, Arabidopsis; D000040:Abscisic Acid; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase
keywords: ABA signaling; ChIP-seq; RNA-seq; WRKY33-mediated resistance; arabidopsis; global Arabidopsis WRKY33 binding sites; plant biology