title: WRKY72-type transcription factors contribute to basal immunity in tomato and Arabidopsis as well as gene-for-gene resistance mediated by the tomato R gene Mi-1.
abstract: WRKY transcription factors play a central role in transcriptional reprogramming associated with plant immune responses. However, due to functional redundancy, typically the contribution of individual members of this family to immunity is only subtle. Using microarray analysis, we found that the paralogous tomato WRKY genes SlWRKY72a and b are transcriptionally up-regulated during disease resistance mediated by the R gene Mi-1. Virus-induced gene silencing of these two genes in tomato resulted in a clear reduction of Mi-1-mediated resistance as well as basal defense against root-knot nematodes (RKN) and potato aphids. Using Arabidopsis T-DNA insertion mutants, we found that their Arabidopsis ortholog, AtWRKY72, is also required for full basal defense against RKN as well as to the oomycete Hyaloperonospora arabidopsidis. Despite their similar roles in basal defense against RKN in both tested plant species, WRKY72-type transcription factors in tomato, but not in Arabidopsis, clearly contributed to basal defense against the bacterial pathogen Pseudomonas syringae. Of the five R genes that we tested in tomato and Arabidopsis, only Mi-1 appeared to be dependent on WRKY72-type transcription factors. Interestingly, AtWRKY72 target genes, identified by microarray analysis of H. arabidopsidis-triggered transcriptional changes, appear to be largely non-responsive to analogs of the defense hormone salicylic acid (SA). Thus, similarly to Mi-1, which in part acts independently of SA, AtWRKY72 appears to utilize SA-independent defense mechanisms. We propose that WRKY72-type transcription factors play a partially conserved role in basal defense in tomato and Arabidopsis, a function that has been recruited to serve Mi-1-dependent immunity.
authors.affiliation: Graduate Program in Plant Pathology, University of California at Riverside, CA 92521, USA.|Department of Nematology, University of California at Riverside, CA 92521, USA.
authors.forename: Kishor K
authors.initials: KK
authors.lastname: Bhattarai
authors.affiliation: Department of Nematology, University of California at Riverside, CA 92521, USA.|Graduate Program in Genetics, Genomics & Bioinformatics, University of California at Riverside, CA 92521, USA.
authors.forename: Hagop S
authors.initials: HS
authors.lastname: Atamian
authors.affiliation: Department of Nematology, University of California at Riverside, CA 92521, USA.|Graduate Program in Genetics, Genomics & Bioinformatics, University of California at Riverside, CA 92521, USA.|Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.|Center for Plant Cell Biology, University of California at Riverside, CA 92521, USA.
authors.forename: Isgouhi
authors.initials: I
authors.lastname: Kaloshian
authors.affiliation: Graduate Program in Genetics, Genomics & Bioinformatics, University of California at Riverside, CA 92521, USA.|Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.|Center for Plant Cell Biology, University of California at Riverside, CA 92521, USA.|Department of Botany and Plant Sciences, University of California at Riverside, CA 92521, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eulgem
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D007113:Immunity, Innate; D018551:Solanum lycopersicum / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009348:Nematoda / Q000472:pathogenicity; D020411:Oligonucleotide Array Sequence Analysis; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D044224:Pseudomonas syringae / Q000472:pathogenicity; D018749:RNA, Plant / Q000235:genetics; D020156:Salicylic Acid / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D010940:Plant Proteins; D018749:RNA, Plant; C036483:T-DNA; D014157:Transcription Factors; D020156:Salicylic Acid
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