Renovell Águeda, Vives Mari Carmen, Ruiz-Ruiz Susana, Navarro Luis, Moreno Pedro, Guerri José
Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Ctra. Moncada-Náquera Km. 4.5, 46113 Moncada, Valencia, Spain.
Virus Genes. 2012 Feb;44(1):131-40. doi: 10.1007/s11262-011-0674-9. Epub 2011 Sep 24.
To counteract plant antiviral defense based on RNA silencing, many viruses express proteins that inhibit this mechanism at different levels. The genome of Citrus leaf blotch virus (CLBV) encodes a 227-kDa protein involved in replication, a 40-kDa movement protein (MP), and a 41-kDa coat protein (CP). To determine if any of these proteins might have RNA silencing suppressor activities, we have used Agrobacterium-mediated transient assays in the green fluorescent protein (GFP)-expressing Nicotiana benthamiana line 16c. Only CLBV MP was able to suppress intracellular GFP silencing induced by expression of either single- or double-stranded (ds) GFP RNA, but not cell-to-cell or long distance spread of the silencing signal. The MP suppressor activity was weak compared to other characterized viral suppressor proteins. Overall our data indicate that MP acts as a suppressor of local silencing probably by interfering in the silencing pathway downstream of the steps of dsRNA and small RNAs generation.
为了对抗基于RNA沉默的植物抗病毒防御，许多病毒表达能在不同水平抑制这种机制的蛋白质。柑橘叶斑病毒（CLBV）的基因组编码一种参与复制的227 kDa蛋白质、一种40 kDa运动蛋白（MP）和一种41 kDa外壳蛋白（CP）。为了确定这些蛋白质中是否有任何一种可能具有RNA沉默抑制活性，我们在表达绿色荧光蛋白（GFP）的本氏烟草16c品系中使用了农杆菌介导的瞬时分析。只有CLBV MP能够抑制由单链或双链（ds）GFP RNA表达诱导的细胞内GFP沉默，但不能抑制沉默信号的细胞间或长距离传播。与其他已鉴定的病毒抑制蛋白相比，MP的抑制活性较弱。总体而言，我们的数据表明，MP可能通过干扰dsRNA和小RNA产生步骤下游的沉默途径，作为局部沉默的抑制剂。
