title: EDM2 is required for RPP7-dependent disease resistance in Arabidopsis and affects RPP7 transcript levels.
abstract: Specific disease resistance of Arabidopsis thaliana against the Hyaloperonospora parasitica isolate Hiks1 (HpHiks1) is mediated by RPP7. Although this disease resistance gene encodes a typical nucleotide binding site leucine-rich repeat (NB-LRR) disease resistance protein, its function is independent of the defense hormone salicylic acid and most known genes required for plant immune responses. We identified EDM2 (enhanced downy mildew 2) in a genetic screen for RPP7 suppressors. Mutations of EDM2 phenocopy RPP7 mutations, but do not affect other tested disease resistance genes. We isolated EDM2 by map-based cloning. The predicted EDM2 protein is structurally unrelated to previously identified components of the plant immune system, bears typical features of transcriptional regulators, including plant homeodomain (PHD)-finger-like domains, and defines a plant-specific protein family. In edm2 mutants both constitutive and HpHiks1-induced RPP7 transcript levels are reduced, suggesting that EDM2 is either a direct or an indirect regulator of RPP7 expression. Microarray analyses defined a set of defense-associated genes, the expression of which is suppressed during successful HpHiks1 colonization of either rpp7 or edm2 plants. This transcriptional phenotype is counteracted by an EDM2/RPP7-dependent mechanism.
authors.affiliation: Department of Biology, CB#3280 University of North Carolina at Chapel Hill, NC 27599, USA. thomas.eulgem@ucr.edu
authors.forename: Thomas
authors.initials: T
authors.lastname: Eulgem
authors.forename: Tokuji
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Wang
authors.forename: Britt
authors.initials: B
authors.lastname: Beasley
authors.forename: Alayne
authors.initials: A
authors.lastname: Cuzick
authors.forename: Mahmut
authors.initials: M
authors.lastname: Tör
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.forename: John M
authors.initials: JM
authors.lastname: McDowell
authors.forename: Eric
authors.initials: E
authors.lastname: Holub
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Dangl
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000469:parasitology* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000378:metabolism*; D032461:Chromosomes, Plant; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D044742:Peronospora / Q000502:physiology*; D010935:Plant Diseases / Q000276:immunology; D016415:Sequence Alignment; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; C523205:EDM2 protein, Arabidopsis; D018398:Homeodomain Proteins; C523204:RPP7 protein, Arabidopsis; D014157:Transcription Factors