Institute of Plant Biology, University of Zurich, 8008 Zurich, Switzerland.
Annu Rev Phytopathol. 2013;51:521-42. doi: 10.1146/annurev-phyto-082712-102312. Epub 2013 May 31.
The ubiquitin-26S proteasome degradation system (UPS) in plants is involved in the signal transduction of many cellular processes, including host immune responses triggered by pathogen attack. Attacking pathogens produce effectors that are translocated into host cells, where they interfere with the host's defense signaling in very specific ways. Perhaps not surprising in view of the broad involvement of the host proteasome in plant immunity, certain bacterial effectors exploit or require the host UPS for their action, as currently best studied in Pseudomonas syringae. Intriguingly, some P. syringae strains also secrete the virulence factor syringolin A, which irreversibly inhibits the proteasome by a novel mechanism. Here, the role of the UPS in plant defense and its exploitation by effectors are summarized, and the biology, taxonomic distribution, and emerging implications for virulence strategies of syringolin A and similar compounds are discussed.
植物的泛素-26S 蛋白酶体降解系统（UPS）参与许多细胞过程的信号转导，包括宿主免疫反应对病原体攻击的触发。攻击宿主的病原体产生效应子，这些效应子被转运到宿主细胞中，以非常特定的方式干扰宿主的防御信号。鉴于宿主蛋白酶体在植物免疫中的广泛参与，某些细菌效应子利用或需要宿主 UPS 来发挥作用，这在目前对丁香假单胞菌的研究中得到了最好的研究。有趣的是，一些丁香假单胞菌菌株还分泌毒力因子丁香菌素 A，它通过一种新的机制不可逆地抑制蛋白酶体。本文总结了 UPS 在植物防御中的作用及其被效应子利用的情况，并讨论了丁香菌素 A 和类似化合物的生物学、分类分布以及对毒力策略的新影响。
