1. Arabidopsis SGT1b is required for defense signaling conferred by several downy mildew resistance genes.
- Author
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Tör M, Gordon P, Cuzick A, Eulgem T, Sinapidou E, Mert-Türk F, Can C, Dangl JL, and Holub EB
- Subjects
- Amino Acid Sequence, Arabidopsis growth & development, Arabidopsis microbiology, Chromosome Mapping, Cloning, Molecular, Cotyledon genetics, Cotyledon growth & development, Cotyledon microbiology, Fungi growth & development, Gene Expression Regulation, Plant, Genetic Complementation Test, Immunity, Innate genetics, Molecular Sequence Data, Mutation, Phenotype, Plant Diseases genetics, Plants, Genetically Modified, Sequence Homology, Amino Acid, Yeasts genetics, Yeasts growth & development, Arabidopsis genetics, Arabidopsis Proteins genetics, Cell Cycle Proteins genetics, Plant Diseases microbiology, Signal Transduction genetics
- 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.
- Published
- 2002
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