Arabidopsis SGT1b is required for defense signaling conferred by several downy mildew resistance genes


TOR M., GORDON P., CUZICK A., EULGEM T., SINAPIDOU E., Mert-Turk F., ...More

PLANT CELL, vol.14, no.5, pp.993-1003, 2002 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 5
  • Publication Date: 2002
  • Doi Number: 10.1105/tpc.001123
  • Journal Name: PLANT CELL
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.993-1003

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.