小GTPase NtRHO1通过与NtWRKY50相互作用负调节烟草对烟草花叶病毒的防御反应

今天介绍的是新发表在JXB，川大席德慧团队发表的研究论文《The small GTPase NtRHO1 negatively regulates tobacco defense response to Tobacco mosaic virus by interacting with NtWRKY50》。

小 GTP 酶在植物生长和发育的调节中起关键作用。然而，植物对病毒感染的响应中小 GTP 酶的机制在很大程度上仍是未知的。 

在本研究中，Rho 型 GTPase NtRHO1 被鉴定为烟草花叶病毒 (TMV) 感染后上调基因之一。NtRHO1的亚细胞定位表明它定位于细胞质、质膜和细胞核。NtRHO1在本氏烟草植物中的瞬时过表达加速了病毒繁殖并导致更多的活性氧产生。相比之下，NtRHO1的沉默降低了本氏烟草植物对 TMV-GFP 的敏感性。

一步的探索表明，NtRHO1 和 NtWRKY50 之间存在直接相互作用，NtWRKY50是本氏烟草植物对病毒感染反应的正调节因子。酵母单杂交和电泳迁移率变化分析表明，该调控与 NtWRKY50s 与 PR1 启动子 WK-box 的结合能力有关，该能力因 NtRHO1 和 NtWRKY50 之间的相互作用而减弱。 

因此，作者探索了一种新的小 GTPase NtRHO1在植物-病原体相互作用中的作用，并提出了其机制。

Small GTPases play critical roles in the regulation of plant growth and development. However, the mechanism of small GTPases in plant response to virus infection remains largely unknown. Here, a Rho-type GTPase NtRHO1 was identified as one of up-regulated genes after tobacco mosaic virus (TMV) infection. Subcellular localization of NtRHO1 showed that it was localized in the cytoplasm, plasma membrane as well as nucleus. Transient overexpression of NtRHO1 in Nicotiana benthamiana plants accelerated virus reproduction and led to more reactive oxygen species production. By contrast, silencing of NtRHO1 reduced the sensitivity of N. benthamiana plants to TMV-GFP. Further explorations showed that there existed a direct interaction between NtRHO1 and NtWRKY50, a positive regulator of N. benthamiana plants response to virus infection. Yeast one-hybrid and electrophoretic mobility shift assays showed that this regulation was related to NtWRKY50’s binding capacity to the WK-box of PR1 promoter, which was weakened by the interaction between NtRHO1 and NtWRKY50. Thus, the role of a novel small GTPase NtRHO1 in the plant-pathogen interaction was explored and its mechanism was proposed.

来源：植物生物学