United States Department of Agriculture, Agricultural Research Service, Lincoln, NE 68583, USA.
Virus Res. 2012 Feb;163(2):672-7. doi: 10.1016/j.virusres.2011.12.019. Epub 2011 Dec 31.
Wheat streak mosaic virus (WSMV) is an eriophyid mite-transmitted virus of the genus Tritimovirus, family Potyviridae. Complete deletion of helper component-proteinase (HC-Pro) has no effect on WSMV virulence or disease synergism, suggesting that a different viral protein suppresses RNA silencing. RNA silencing suppression assays using Nicotiana benthamiana 16C plants expressing GFP were conducted with each WSMV protein; only P1 suppressed RNA silencing. Accumulation of GFP siRNAs was markedly reduced in leaves infiltrated with WSMV P1 at both 3 and 6 days post infiltration relative to WSMV HC-Pro and the empty vector control. On the other hand, helper component-proteinase (HC-Pro) of two species in the mite-transmitted genus Rymovirus, family Potyviridae was demonstrated to be a suppressor of RNA silencing. Symptom enhancement assays were conducted by inoculating Potato virus X (PVX) onto transgenic N. benthamiana. Symptoms produced by PVX were more severe on transgenic plants expressing WSMV P1 or potyvirus HC-Pro compared to transgenic plants expressing GFP or WSMV HC-Pro.
小麦线条花叶病毒（WSMV）是一种属于Tritimovirus 属的、被叶螨传播的病毒，属于马铃薯 Y 病毒科。辅助蛋白酶（HC-Pro）的完全缺失对 WSMV 的毒力或疾病协同作用没有影响，这表明一种不同的病毒蛋白抑制了 RNA 沉默。使用表达 GFP 的 Nicotiana benthamiana 16C 植物进行了 RNA 沉默抑制测定，对每个 WSMV 蛋白进行了测定；只有 P1 抑制了 RNA 沉默。与 WSMV HC-Pro 和空载体对照相比，在 3 天和 6 天渗透后，与 WSMV P1 共渗透的叶片中 GFP siRNA 的积累明显减少。另一方面，已证明 mite-transmitted 属 Rymovirus 家族中的两种马铃薯 Y 病毒科的辅助蛋白酶（HC-Pro）是 RNA 沉默的抑制剂。通过将马铃薯 X 病毒（PVX）接种到转基因 N. benthamiana 上进行了症状增强测定。与表达 GFP 或 WSMV HC-Pro 的转基因植物相比，表达 WSMV P1 或马铃薯 Y 病毒科 HC-Pro 的转基因植物上产生的 PVX 症状更为严重。
