Multiple Functions of Rice Dwarf Phytoreovirus Pns10 in Suppressing Systemic RNA Silencing
Multiple Functions of Rice Dwarf Phytoreovirus Pns10 in Suppressing Systemic RNA Silencing
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水稻矮化植物呼肠孤病毒 Pns10 抑制系统性 RNA 沉默的多种功能
DOI：
10.1128/jvi.00864-10
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发表时间：
2010-12-01
影响因子：
5.4
通讯作者：
Li, Yi
中科院分区：
文献类型：
--
作者：
Ren, Bo;Guo, Yuanyuan;Li, Yi
RNA沉默是植物和其他生物抗病毒防御反应的一种有效机制。为了防御，病毒已经进化出多种RNA沉默抑制子（VSR），其可以抑制沉默途径的不同步骤。我们以前确定Pns 10编码的水稻矮植物呼肠孤病毒（RDV）作为VSR，它的第一种双链RNA（dsRNA）病毒。在这项研究中，我们研究了Pns 10的功能，在抑制系统RNA沉默在广泛使用的烟草本塞曼模式植物的机制。我们报告说，Pns 10抑制本地和系统RNA沉默引发的正义mRNA，增强病毒复制和/或病毒RNA的稳定性，在接种的叶子，加速病毒感染的系统传播，并使病毒入侵茎尖。从机制上讲，Pns 10干扰受体组织中沉默信号的感知，结合具有两个核苷酸3'突出端的双链小干扰RNA（siRNA），并导致RDR 6表达下调。这些结果显著加深了我们对dsRNA病毒编码的VSR功能的机制理解，并提供了额外的证据，证明结合siRNA和干扰RDR 6表达是不同病毒组编码的VSR功能的广泛机制。
RNA silencing is a potent mechanism of antiviral defense response in plants and other organisms. For counterdefense, viruses have evolved a variety of suppressors of RNA silencing (VSRs) that can inhibit distinct steps of a silencing pathway. We previously identified Pns10 encoded by Rice dwarf phytoreovirus (RDV) as a VSR, the first of its kind from double-stranded RNA (dsRNA) viruses. In this study we investigated the mechanisms of Pns10 function in suppressing systemic RNA silencing in the widely used Nicotiana benthamiana model plant. We report that Pns10 suppresses local and systemic RNA silencing triggered by sense mRNA, enhances viral replication and/or viral RNA stability in inoculated leaves, accelerates the systemic spread of viral infection, and enables viral invasion of shoot apices. Mechanistically, Pns10 interferes with the perception of silencing signals in recipient tissues, binds double-stranded small interfering RNA (siRNAs) with two-nucleotide 3' overhangs, and causes the downregulated expression of RDR6. These results significantly deepen our mechanistic understanding of the VSR functions encoded by a dsRNA virus and contribute additional evidence that binding siRNAs and interfering with RDR6 expression are broad mechanisms of VSR functions encoded by diverse groups of viruses.