Henan Provincial Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou 450009, Henan, China.
Centro de Edafología y Biología Aplicada del Segura-CSIC, 30100 Espinardo, Murcia, Spain.
Phytopathology. 2019 Sep;109(9):1648-1657. doi: 10.1094/PHYTO-11-18-0436-R. Epub 2019 Aug 5.
Cucumber green mottle mosaic virus (CGMMV), a member of the genus (family Virgaviridae), is an economically important virus that has detrimental effects on cucurbit crops worldwide. Understanding the interaction between host factors and CGMMV viral proteins will facilitate the design of new strategies for disease control. In this study, a yeast two-hybrid assay revealed that the CGMMV helicase (HEL) domain interacts with a small heat shock protein (sHSP), and we verified this observation by performing in vitro GST pull-down and in vivo coimmunoprecipitation assays. Measurement of the levels of accumulated sHSP transcript revealed that is upregulated on initial CGMMV infection in both and plants, although not in the systemically infected leaves. We also found that the subcellular localization of the sHSP was altered after CGMMV infection. To further validate the role of sHSP in CGMMV infection, we produced and assayed transgenic plants with up- and down-regulated sHSP expression. Overexpression of sHSP inhibited viral RNA accumulation and retarded disease development, whereas sHSP silencing had no marked effect on CGMMV infection. Therefore, we postulate that the identified sHSP may be one of the factors modulating host defense mechanisms in response to CGMMV infection and that the HEL domain interaction may inhibit this sHSP function to promote viral infection.
黄瓜绿斑驳花叶病毒（CGMMV），是一种属于（病毒科）的病毒，是一种对全球葫芦科作物具有经济危害性的病毒。了解宿主因子与 CGMMV 病毒蛋白之间的相互作用，将有助于设计新的疾病控制策略。在这项研究中，酵母双杂交分析表明 CGMMV 解旋酶（HEL）结构域与小热休克蛋白（sHSP）相互作用，我们通过体外 GST 下拉和体内共免疫沉淀实验验证了这一观察结果。检测 sHSP 转录物的积累水平表明，在 CGMMV 初始感染时，和 植物中的 上调，尽管在系统感染的叶片中没有上调。我们还发现，在 CGMMV 感染后，sHSP 的亚细胞定位发生改变。为了进一步验证 sHSP 在 CGMMV 感染中的作用，我们产生并分析了过表达和下调 sHSP 表达的 转基因植物。sHSP 的过表达抑制了病毒 RNA 的积累并延缓了疾病的发展，而 sHSP 的沉默对 CGMMV 感染没有明显影响。因此，我们推测，所鉴定的 sHSP 可能是调节宿主防御机制以响应 CGMMV 感染的因素之一，而 HEL 结构域的相互作用可能抑制了这种 sHSP 功能，从而促进了病毒的感染。
