Tör Mahmut, Gordon Pam, Cuzick Alayne, Eulgem Thomas, Sinapidou Evaggelia, Mert-Türk Figen, Can Canan, Dangl Jeffery L, Holub Eric B
Plant Genetics and Biotechnology Department, Horticulture Research International, Wellesbourne, Warwick CV35 9EF, United Kingdom.
Plant Cell. 2002 May;14(5):993-1003. doi: 10.1105/tpc.001123.
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.
我们描述了在拟南芥生态型哥伦比亚（Col-0）中鉴定出的一个突变体，该突变体对几种寄生霜霉分离株表现出增强的霜霉病易感性（edm1），包括RPP7诊断分离株Hiks1。该突变被定位到第四条染色体上，通过物理特征分析为一个跨越七个基因的35kb缺失。其中一个基因使突变体对所有测试的寄生霜霉分离株恢复到完全野生型抗性。这个基因（AtSGT1b）编码一个预测分子量为39.8kD的蛋白质，是酵母SGT1在拟南芥中的直系同源物，酵母SGT1最初被描述为着丝粒功能和泛素介导的蛋白水解中的关键调节蛋白。AtSGT1b在N端包含三个四肽重复序列，随后是一个含二分弦的SGT结构域和一个位于C端的SGT特异性结构域。我们讨论了AtSGT1b在抗病性中的作用及其可能参与植物泛素介导的蛋白水解过程。
