title: Transcriptional reprogramming regulated by WRKY18 and WRKY40 facilitates powdery mildew infection of Arabidopsis.
abstract: The two closely related Arabidopsis transcription factors, WRKY18 and WRKY40, play a major and partly redundant role in PAMP-triggered basal defense. We monitored the transcriptional reprogramming induced by the powdery mildew fungus, Golovinomyces orontii, during early stages of infection with respect to the role of WRKY18/40. Expression of >1300 Arabidopsis genes was differentially altered already 8 hours post infection (hpi), indicating rapid pre-penetration signaling between the pathogen and the host. We found that WRKY18/40 negatively affects pre-invasion host defenses and deduced a subset of genes that appear to be under WRKY18/40 control. A mutant lacking the WRKY18/40 repressors executes pathogen-dependent but exaggerated expression of some defense genes leading, for example, to strongly elevated levels of camalexin. This implies that WRKY18/40 act in a feedback repression system controlling basal defense. Moreover, using chromatin immunoprecipitation (ChIP), direct in vivo interactions of WRKY40 to promoter regions containing W box elements of the regulatory gene EDS1, the AP2-type transcription factor gene RRTF1 and to JAZ8, a member of the JA-signaling repressor gene family were demonstrated. Our data support a model in which WRKY18/40 negatively modulate the expression of positive regulators of defense such as CYP71A13, EDS1 and PAD4, but positively modulate the expression of some key JA-signaling genes by partly suppressing the expression of JAZ repressors.
authors.affiliation: Department of Plant Microbe Interaction, Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, Cologne 50829, Germany.
authors.forename: Shree P
authors.initials: SP
authors.lastname: Pandey
authors.forename: Mario
authors.initials: M
authors.lastname: Roccaro
authors.forename: Moritz
authors.initials: M
authors.lastname: Schön
authors.forename: Elke
authors.initials: E
authors.lastname: Logemann
authors.forename: Imre E
authors.initials: IE
authors.lastname: Somssich
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001203:Ascomycota / Q000472:pathogenicity*; D003517:Cyclopentanes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions; D007211:Indoles / Q000032:analysis; D009154:Mutation; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D013844:Thiazoles / Q000032:analysis; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000094162:Phytoalexins
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D004268:DNA-Binding Proteins; D007211:Indoles; D054883:Oxylipins; D013844:Thiazoles; D014157:Transcription Factors; C118837:EDS1 protein, Arabidopsis; C464509:WRKY18 protein, Arabidopsis; C512070:WRKY40 protein, Arabidopsis; C102405:camalexin; D000094162:Phytoalexins; C011006:jasmonic acid