Department of Plant Pathology, University of Kentucky, Lexington, KY, USA.
College of Agronomy and Biotechnology, Southwest University, Chongqing, China.
J Exp Bot. 2019 Mar 11;70(5):1627-1638. doi: 10.1093/jxb/erz019.
The Arabidopsis plasma membrane-localized resistance protein RPM1 is degraded upon the induction of the hypersensitive response (HR) triggered in response to its own activation or that of other unrelated resistance (R) proteins. We investigated the role of RPM1 turnover in RPM1-mediated resistance and showed that degradation of RPM1 is not associated with HR or resistance mediated by this R protein. Likewise, the runaway cell death phenotype in the lsd1 mutant was not associated with RPM1 degradation and did not alter RPM1-derived resistance. RPM1 stability and RPM1-mediated resistance were dependent on the double-stranded RNA binding (DRB) proteins 1 and 4. Interestingly, the function of DRB1 in RPM1-mediated resistance was not associated with its role in pre-miRNA processing. The DRB3 and DRB5 proteins negatively regulated RPM1-mediated resistance and a mutation in these completely or partially restored resistance in the drb1, drb2, and drb4 mutant backgrounds. Conversely, plants overexpressing DRB5 showed attenuated RPM1-mediated resistance. A similar role for DRBs in basal and R-mediated resistance suggests that these proteins play a general role in bacterial resistance.
拟南芥质膜定位的抗性蛋白 RPM1 在自身激活或其他不相关的抗性 (R) 蛋白激活引发的过敏反应 (HR) 诱导下会被降解。我们研究了 RPM1 周转在 RPM1 介导的抗性中的作用，并表明 RPM1 的降解与 HR 或该 R 蛋白介导的抗性无关。同样，lsd1 突变体中的失控细胞死亡表型与 RPM1 降解无关，也不会改变 RPM1 衍生的抗性。RPM1 的稳定性和 RPM1 介导的抗性依赖于双链 RNA 结合 (DRB) 蛋白 1 和 4。有趣的是，DRB1 在 RPM1 介导的抗性中的功能与其在 pre-miRNA 加工中的作用无关。DRB3 和 DRB5 蛋白负调控 RPM1 介导的抗性，这些蛋白的突变完全或部分恢复了 drb1、drb2 和 drb4 突变体背景中的抗性。相反，过表达 DRB5 的植物表现出 RPM1 介导的抗性减弱。DRBs 在基础和 R 介导的抗性中具有相似的作用，表明这些蛋白在细菌抗性中发挥一般作用。
