High Plains wheat mosaic virus (HPWMoV, genus Emaravirus; family Fimoviridae), transmitted by the wheat curl mite (Aceria tosichella Keifer), harbors a monocistronic octapartite single-stranded negative-sense RNA genome. In this study, putative proteins encoded by HPWMoV genomic RNAs 2–8 were screened for potential RNA silencing suppression activity by using a green fluorescent protein-based reporter agroinfiltration assay. We found that proteins encoded by RNAs 7 (P7) and 8 (P8) suppressed silencing induced by single- or double-stranded RNAs and efficiently suppressed the transitive pathway of RNA silencing. Additionally, a Wheat streak mosaic virus (WSMV, genus Tritimovirus; family Potyviridae) mutant lacking the suppressor of RNA silencing (ΔP1) but having either P7 or P8 from HPWMoV restored cell-to-cell and long-distance movement in wheat, thus indicating that P7 or P8 rescued silencing suppressor-deficient WSMV. Furthermore, HPWMoV P7 and P8 substantially enhanced the pathogenicity of Potato virus X in Nicotiana benthamiana. Collectively, these data demonstrate that the octapartite genome of HPWMoV encodes two suppressors of RNA silencing.

高平原小麦花叶病毒（HPWMoV，属Emaravirus ;家庭Fimoviridae） ，由小麦卷叶螨（发送螨tosichella螨），怀有单顺反子octapartite单链负链RNA基因组。在这项研究中，通过使用基于绿色荧光蛋白的报告基因农杆菌浸润试验，筛选了由HPWMoV基因组RNA 2-8编码的假定蛋白是否具有潜在的RNA沉默抑制活性。我们发现由RNA 7（P7）和8（P8）编码的蛋白质抑制了单链或双链RNA诱导的沉默，并有效地抑制了RNA沉默的传递途径。另外，小麦条纹花叶病毒（WSMV，Tritimovirus属；家族）Potyviridae突变体缺乏RNA沉默抑制子（ΔP1），但具有来自HPWMoV的P7或P8恢复了小麦中的细胞间和长距离运动，因此表明P7或P8拯救了沉默抑制子缺失的WSMV。此外，HPWMoV P7和P8显着增强的致病性马铃薯X病毒在本塞姆氏烟草。总体而言，这些数据表明，HPWMoV的八聚体基因组编码了两种RNA沉默抑制子。