title: Arabidopsis SGT1b is required for defense signaling conferred by several downy mildew resistance genes.
abstract: We describe the identification of a mutant in the Arabidopsis accession Columbia (Col-0) that exhibits enhanced downy mildew (edm1) susceptibility to several Peronospora parasitica isolates, including the RPP7-diagnostic isolate Hiks1. The mutation was mapped to chromosome IV and characterized physically as a 35-kb deletion spanning seven genes. One of these genes complemented the mutant to full wild-type resistance against all of the Peronospora isolates tested. This gene (AtSGT1b) encodes a predicted protein of 39.8 kD and is an Arabidopsis ortholog of yeast SGT1, which was described originally as a key regulatory protein in centromere function and ubiquitin-mediated proteolysis. AtSGT1b contains three tetratricopeptide repeats at the N terminus followed by a bipartite chord-containing SGT domain and an SGT-specific domain at the C terminus. We discuss the role of AtSGT1b in disease resistance and its possible involvement in ubiquitin-mediated proteolysis in plants.
authors.affiliation: Plant Genetics and Biotechnology Department, Horticulture Research International, Wellesbourne, Warwick CV35 9EF, United Kingdom.
authors.forename: Mahmut
authors.initials: M
authors.lastname: Tör
authors.forename: Pam
authors.initials: P
authors.lastname: Gordon
authors.forename: Alayne
authors.initials: A
authors.lastname: Cuzick
authors.forename: Thomas
authors.initials: T
authors.lastname: Eulgem
authors.forename: Evaggelia
authors.initials: E
authors.lastname: Sinapidou
authors.forename: Figen
authors.initials: F
authors.lastname: Mert-Türk
authors.forename: Canan
authors.initials: C
authors.lastname: Can
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Dangl
authors.forename: Eric B
authors.initials: EB
authors.lastname: Holub
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development / Q000382:microbiology; D005658:Fungi / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics*; D015003:Yeasts / Q000235:genetics / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C452192:SGT1b protein, Arabidopsis