小G蛋白Rops基因在番茄抗白粉病中的作用及其调控机理研究

The occurrence of the tomato powdery mildew has become more and more serious in greenhouse, while the resistance mechanism study of tomato against the powdery mildew fungus Oidium neolycopersici is greatly retarded. Small GTP-binding protein genes Rops are improtant regulatory factors that are involved in plant defense responses. Actin filament polymerization has been proved to play an important role in plant against pathogen infection in our previous study. The polymerization of actin is regulated by actin-related protein complex Arp2/3 and Arp2/3 gene expression is regulated by upstream factor Rops. However, whether small GTP-binding protein Rops participate in defense responses through regulation of the actin rearrangement largely remains unclear. This project attempts to reveal roles of Rops genes in resistance of tomato against the powdery mildew and in regulation of actin filaments rearrangement by through virus-induced gene silencing and Arp2/3 and Rops gene expression with the actin polymerization in plants. Arabidopsis mutants are used to confirm the function of Rops gene again. This research is in the hope of clarification the resistance mechanisms of tomato against the powdery mildew fungus from a novel angle, further enriching the tomato disease resistance signaling network mediated by small GTP-binding proteins Rops, as well as providing reference to the similar researches.

番茄白粉病发生日趋严重，而番茄抗白粉病机制研究却明显滞后。小G蛋白是植物防卫反应中重要的调控因子。前期研究发现，微丝骨架的聚合在植物抗病性中具有重要作用，其受微丝相关蛋白Arp2/3复合体的调控，而小G蛋白Rops基因作为上游因子调控Arp2/3基因表达。然而，小G蛋白Rops是否直接通过调控微丝骨架重组来参与防卫反应目前尚不清楚。本项目拟通过病毒介导的基因沉默以及Rops和Arp2/3等相关基因的表达，揭示Rops基因在番茄抗白粉病中的作用及其调控微丝骨架重组作用；微丝骨架的解聚和聚合对于Rops和Arp2/3基因表达的影响；通过拟南芥突变体验证其功能。本项目的实施，将以全新的角度揭示番茄抗白粉病机理，进一步丰富小G蛋白Rops介导的番茄抗病信号网络，也可为同类研究提供借鉴。

番茄白粉病发生日趋严重，揭示番茄抗白粉菌侵染的分子机理对于植物抗病性研究具有重要的意义。本研究通过RT-qPCR发现，小G蛋白SlRop1、SlRop7、SlRop9和SlRop10基因，微丝相关蛋白Arp2/3复合体的SlArpC3和SlArpC4基因与番茄抗白粉病相关；VIGS试验表明沉默SlRops基因，番茄抗白粉性降低，并且SlArpCs和PRs基因呈下调表达，表明SlRops与SlArpCs的互作及其与抗病性的关系。说明番茄的小G蛋白SlRops基因通过调控微丝相关蛋白Arp2/3复合体基因表达，来调控微丝骨架的重组。通过SlArpCs基因沉默和抗病相关基因的表达研究，也验证其与抗病性相关。GFP标记的载体融合后转化番茄原生质体，将SlRop7和SlRop10分别定位于细胞膜和细胞核；拟南芥突变体功能验证表明，AtRop11、AtArpC2B和AtArpC3突变体抗白粉性降低；此外，微丝骨架的解聚降低了小麦对番茄白粉病的抗性。共发表5篇学术论文，其中SCI论文4篇。通过综合研究认为，本项目研究以全新的角度揭示番茄抗白粉病机理，推进了植物抗病性研究进程。