The effector AWR5 from the plant pathogen Ralstonia solanacearum is an inhibitor of the TOR signalling pathway.
The effector AWR5 from the plant pathogen Ralstonia solanacearum is an inhibitor of the TOR signalling pathway.
复制标题
来自植物病原体摩尔斯通病原体的效应AWR5是TOR信号通路的抑制剂。
DOI：
10.1038/srep27058
复制
发表时间：
2016-06-03
影响因子：
4.6
通讯作者：
Valls M
中科院分区：
文献类型：
--
作者：
Popa C;Li L;Gil S;Tatjer L;Hashii K;Tabuchi M;Coll NS;Ariño J;Valls M
细菌病原体具有复杂的III型效应物(T3E)，它们被转移到宿主细胞内导致疾病。然而，这些效应器中只有一小部分被指定了功能。在这里，我们证明了来自植物病原体青枯雷尔氏菌的T3E AWR5是TOR的抑制剂，TOR是真核生物中的一种中央调节因子，控制细胞生长和胁迫反应之间的切换，以响应营养的可获得性。AWR5在酵母中的异源表达导致了生长抑制和自噬诱导，并伴随着大量的转录变化，这无疑让人想起雷帕霉素或氮饥饿对TOR的抑制。对酵母中这些表型的详细遗传分析，包括编码PP2A磷酸酶调节亚基的CDC55和TPD3突变对AWR5诱导的毒性的抑制，表明AWR5可能通过直接或间接抑制PP2A上游的TOR途径来发挥其功能。我们在PLANTA中提供的证据表明，这种T3E导致TOR调节的植物硝酸还原酶活性下降，而且植物中正常水平的TOR和CDC55同系物是青枯病菌致病所必需的。我们的结果表明TOR途径是一个真正的T3E靶点，并进一步证明酵母是一个有用的平台来表征T3E功能。
Bacterial pathogens possess complex type III effector (T3E) repertoires that are translocated inside the host cells to cause disease. However, only a minor proportion of these effectors have been assigned a function. Here, we show that the T3E AWR5 from the phytopathogen Ralstonia solanacearum is an inhibitor of TOR, a central regulator in eukaryotes that controls the switch between cell growth and stress responses in response to nutrient availability. Heterologous expression of AWR5 in yeast caused growth inhibition and autophagy induction coupled to massive transcriptomic changes, unmistakably reminiscent of TOR inhibition by rapamycin or nitrogen starvation. Detailed genetic analysis of these phenotypes in yeast, including suppression of AWR5-induced toxicity by mutation of CDC55 and TPD3, encoding regulatory subunits of the PP2A phosphatase, indicated that AWR5 might exert its function by directly or indirectly inhibiting the TOR pathway upstream PP2A. We present evidence in planta that this T3E caused a decrease in TOR-regulated plant nitrate reductase activity and also that normal levels of TOR and the Cdc55 homologues in plants are required for R. solanacearum virulence. Our results suggest that the TOR pathway is a bona fide T3E target and further prove that yeast is a useful platform for T3E function characterisation.