PLoS Pathogens:南京农业大学陶小荣教授研究组揭示植物负义链RNA病

摘要 : 2016年2月10日，国际病原物顶级学术杂志《PLoS Pathogens》在线发表南京农业大学植物病毒学实验室陶小荣教授课题组的一项最新研究成果。本研究首次揭示了植物内质网结构在植物负义链RNA病毒胞间运动中的作用，为阐明植物负义链RNA病毒胞间运动机制奠定了重要基础。

2016年2月10日，国际病原物顶级学术杂志《PLoS Pathogens》在线发表南京农业大学植物病毒学实验室陶小荣教授课题组的一项最新研究成果。本研究首次揭示了植物内质网结构在植物负义链RNA病毒胞间运动中的作用，为阐明植物负义链RNA病毒胞间运动机制奠定了重要基础。论文题为《The ER-Membrane Transport System Is Critical for Intercellular Trafficking of the NSm Movement Protein and Tomato Spotted Wilt Tospovirus》。南京农业大学植保学院博士生冯致科为第一作者，陶小荣教授为通讯作者。

植物负义链RNA病毒是一类农业生产上非常重要的植物病毒，引致的病毒病害每年在世界范围内对农业作物造成重大的经济损失;同时该类病毒因其基因组结构独特，因此又具有重要的研究价值。陶小荣教授研究组以番茄斑萎病毒作为模式，研究植物负义链RNA病毒的移动、复制和致病等机制。

该团队曾于2013年在《New Phytologist》上揭示番茄斑萎病毒的核衣壳蛋白借助于植物胞内的内质网结构帮助病毒完成胞内运动“Nucleocapsid of Tomato spotted wilt tospovirus forms mobile particles that traffic on an actin/endoplasmic reticulum network driven by myosin XI-K”。该团队在原有研究的基础上，进一步研究了该病毒的胞间运动机制。植物细胞的内质网结构相对于动物细胞具有非常独特的特性：植物的每一个细胞的内质网是通过胞间连丝中的连丝微管(Desmotubule, 一种内质网变体)相连的，因此植物内质网结构在所有的细胞中都是相连的，这使得内质网在植物中形成一个巨大的网络。在本研究中，研究人员发现，番茄斑萎病毒正是借助于植物的这一特有结构——胞间相互连通的内质网网络运输系统，帮助病毒完成胞间运动;同时，该研究揭示，胞间相互连通的内质网网络可以作为蛋白质胞间运动的重要运输路径。

原文链接：

The ER-Membrane Transport System Is Critical for InterCellular Trafficking of the NSm Movement Protein and Tomato Spotted Wilt Tospovirus

原文摘要：

Plant viruses move through plasmodesmata to infect new cells. The plant endoplasmic reticulum (ER) is interconnected among cells via the ER desmotubule in the plasmodesma across the cell wall, forming a continuous ER network throughout the entire plant. This ER continuity is unique to plants and has been postulated to serve as a platform for the intercellular trafficking of macromolecules. In the present study, the contribution of the plant ER membrane transport system to the intercellular trafficking of the NSm movement protein and Tomato spotted wilt tospovirus (TSWV) is investigated. We showed that TSWV NSm is physically associated with the ER membrane in Nicotiana benthamiana plants. An NSm-GFP fusion protein transiently expressed in single leaf cells was trafficked into neighboring cells. Mutations in NSm that impaired its association with the ER or caused its mis-localization to other subcellular sites inhibited cell-to-cell trafficking. Pharmacological disruption of the ER network severely inhibited NSm-GFP trafficking but not GFP diffusion. In the Arabidopsis thalianamutant rhd3 with an impaired ER network, NSm-GFP trafficking was significantly reduced, whereas GFP diffusion was not affected. We also showed that the ER-to-Golgi secretion pathway and the cytoskeleton transport systems were not involved in the intercellular trafficking of TSWV NSm. Importantly, TSWV cell-to-cell spread was delayed in the ER-defective rhd3mutant, and this reduced viral infection was not due to reduced replication. On the basis of robust biochemical, cellular and genetic analysis, we established that the ER membrane transport system serves as an important direct route for intercellular trafficking of NSm and TSWV.

DOI:10.1371/journal.ppat.1005443

作者：陶小荣

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