Abstract
SGT1 (suppressor of the G2 allele of skp1) has an important role in resistance gene-mediated and non-host resistance in plants. To elucidate the role of SGT1 in the interaction between Nicotiana plants and Ralstonia solanacearum (Rs), we isolated NbSGT1 (Nicotiana benthamiana SGT1) from N. benthamiana. When challenged with non-pathogenic Rs strain 8107 that induced a hypersensitive response in N. benthamiana, expression of defense-related genes including PR-1, PR-4, hsr203J, hin1, WIPK, and EREBP was enhanced in the NbSGT1-silenced plants compared to control plants. The expression of defense-related genes was also enhanced in the silencing plants challenged with pathogenic strain OE1-1 of Rs. In addition, the development of wilt symptoms was significantly delayed in NbSGT1-silencing plants. Therefore NbSGT1 might be involved in negative control of defense response in N. benthamiana during both non-host and susceptible Rs-Nicotiana plant interactions.
