病毒蛋白p24通过与葡萄VvARF互作抑制寄主防卫反应的分子机制

葡萄卷叶病是葡萄上广泛发生的严重病毒病害，其相关重要病原物之一为葡萄卷叶伴随病毒2号（GLRaV-2）。通过揭示病毒的侵染机制、进而建立有效的抗病毒策略和防控技术是病毒病研究领域的前沿热点。本课题组前期研究结果表明，GLRaV-2编码的RNA沉默抑制子p24通过与负调控葡萄PR1基因的VvARF互作而帮助病毒侵染，初步揭示了GLRaV-2对葡萄的致病途径。本研究拟在此基础上，首先克隆葡萄PR1基因启动子序列及SA途径的关键调控因子基因，然后通过体内和体外生化实验解析p24/VvARF互作对寄主SA防御反应的抑制及其作用机制；同时利用分子杂交及转基因等技术手段，阐明p24/VvARF互作对葡萄植物抗病毒RNA沉默的抑制及其作用机制。最终揭示GLRaV-2通过其p24蛋白操控一个寄主因子来抑制葡萄的双重防御途径、进而成功侵染的新机制。研究结果可为发展该病毒病害防控策略提供新思路和新靶标。

Grapevine leafroll disease is an economically important disease in cultivated grapevines worldwide, and grapevine leafroll-associated virus 2 (GLRaV-2) is considered as one of the most prevalent viruses associated with the disease. Exploring the molecular mechanisms underlying viral infection for developing effective antiviral strategies is a research hotspot. Our previous works showed that the RNA silencing suppressor p24 protein encoded by GLRaV-2 promotes viral infection via interaction with VvARF, a grapevine transcription factor that negatively regulates the expression of PR1. In this study, based on above results, the promoter region of PR1 gene and genes encoding key regulators of salicylic acid (SA) signaling pathway will be cloned, and the effects of p24/VvARF interaction on SA defense response and its underlying mechanism will then be explored using biochemistry experiments both in vivo and vitro. In addition, the effects of p24/VvARF interaction on suppression of host antiviral RNA silencing and its underlying mechanism will also be revealed through molecular blotting hybridization technology, and transient and stable transformation methods. The outcome of this research will provide an novel mechanism by which GLRaV-2 blocks both SA-mediated defense and antiviral RNA silencing in grapevine via p24’s targeting one host factor, which offers new thoughts and a potential target for developing effective antiviral strategies to control the disease.