title: Analyses of wrky18 wrky40 plants reveal critical roles of SA/EDS1 signaling and indole-glucosinolate biosynthesis for Golovinomyces orontii resistance and a loss-of resistance towards Pseudomonas syringae pv. tomato AvrRPS4.
abstract: Simultaneous mutation of two WRKY-type transcription factors, WRKY18 and WRKY40, renders otherwise susceptible wild-type Arabidopsis plants resistant towards the biotrophic powdery mildew fungus Golovinomyces orontii. Resistance in wrky18 wrky40 double mutant plants is accompanied by massive transcriptional reprogramming, imbalance in salicylic acid (SA) and jasmonic acid (JA) signaling, altered ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) expression, and accumulation of the phytoalexin camalexin. Genetic analyses identified SA biosynthesis and EDS1 signaling as well as biosynthesis of the indole-glucosinolate 4MI3G as essential components required for loss-of-WRKY18 WRKY40-mediated resistance towards G. orontii. The analysis of wrky18 wrky40 pad3 mutant plants impaired in camalexin biosynthesis revealed an uncoupling of pre- from postinvasive resistance against G. orontii. Comprehensive infection studies demonstrated the specificity of wrky18 wrky40-mediated G. orontii resistance. Interestingly, WRKY18 and WRKY40 act as positive regulators in effector-triggered immunity, as the wrky18 wrky40 double mutant was found to be strongly susceptible towards the bacterial pathogen Pseudomonas syringae DC3000 expressing the effector AvrRPS4 but not against other tested Pseudomonas strains. We hypothesize that G. orontii depends on the function of WRKY18 and WRKY40 to successfully infect Arabidopsis wild-type plants while, in the interaction with P. syringae AvrRPS4, they are required to mediate effector-triggered immunity.
authors.affiliation: Department of Plant Microbe Interaction, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Schön
authors.forename: Armin
authors.initials: A
authors.lastname: Töller
authors.forename: Celia
authors.initials: C
authors.lastname: Diezel
authors.forename: Charlotte
authors.initials: C
authors.lastname: Roth
authors.forename: Lore
authors.initials: L
authors.lastname: Westphal
authors.forename: Marcel
authors.initials: M
authors.lastname: Wiermer
authors.forename: Imre E
authors.initials: IE
authors.lastname: Somssich
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001203:Ascomycota / Q000235:genetics / Q000472:pathogenicity*; D020171:Botrytis / Q000472:pathogenicity; D003517:Cyclopentanes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D060467:Disease Resistance; D018506:Gene Expression Regulation, Plant; D005961:Glucosinolates / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D009154:Mutation; D009868:Oomycetes / Q000472:pathogenicity; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000032:analysis / Q000378:metabolism; D018515:Plant Leaves; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000235:genetics / Q000472:pathogenicity*; D020156:Salicylic Acid / Q000032:analysis / Q000378:metabolism; D015398:Signal Transduction; D013844:Thiazoles / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000094162:Phytoalexins
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D004268:DNA-Binding Proteins; D005961:Glucosinolates; D007211:Indoles; D054883:Oxylipins; D010937:Plant Growth Regulators; D020156:Salicylic Acid; D013844:Thiazoles; D014157:Transcription Factors; C118837:EDS1 protein, Arabidopsis; C464509:WRKY18 protein, Arabidopsis; C512070:WRKY40 protein, Arabidopsis; C102405:camalexin; D000094162:Phytoalexins; C011006:jasmonic acid; C030374:indole