The Tobacco mosaic virus 126-kDa protein associated with virus replication and movement suppresses RNA silencing
The Tobacco mosaic virus 126-kDa protein associated with virus replication and movement suppresses RNA silencing
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DOI：
10.1094/mpmi.2004.17.6.583
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发表时间：
2004-06-01
影响因子：
3.5
通讯作者：
Nelson, RS
中科院分区：
文献类型：
--
作者：
Ding, XS;Liu, JZ;Nelson, RS
烟草的系统症状。烟草花叶病毒（TMV）的黄原胶是由一个或两个氨基共末端的病毒126-和183-kDa蛋白调节：蛋白质参与病毒复制和细胞间的运动。在这里，我们比较系统的积累和基因沉默特性的TMV株系和突变体，表达改变126-和183-kDa的蛋白质，并诱导不同强度的系统症状N。烟草通过嫁接试验，确定了M-IC-1，3，一种在局部积累而不引起系统症状的TMV掩蔽株系的突变体，通过维管组织移动，但未能在系统叶中积累到高水平。系统性叶片中M（IC）1，3积累的缺乏与该组织中的RNA沉默活性相关，通过病毒特异性的约25个核苷酸的RNA的出现和表达与绿色荧光蛋白（GFP）融合的126-kDa蛋白的转基因植物的叶片的荧光损失。TMV株系和突变体在126-kDa蛋白开放阅读框中改变引起系统症状的能力与它们瞬时延长126-kDa蛋白：GFP融合体表达和瞬时抑制转基因N.烟草和转基因烟草。benthamiana，分别。在N. benthamiana只发生在病毒积累到高水平的地方。使用农杆菌渗透测定，确定单独的126-kDa蛋白质可以延迟GFP沉默。基于这些结果和已知的TMV和其他病毒之间的协同作用，抑制的机制，由126-kDa的蛋白质进行了比较，与那些利用其他最初的特征抑制RNA沉默。
Systemic symptoms induced on Nicotiana tabacum cv. Xanthi by Tobacco mosaic virus (TMV) are modulated by one or both amino-coterminal viral 126- and 183-kDa proteins: proteins involved in virus replication and cell-to-cell movement. Here we compare the systemic accumulation and gene silencing characteristics of TMV strains and mutants that express altered 126- and 183-kDa proteins and induce varying intensities of systemic symptoms on N. tabacum. Through grafting experiments, it was determined that M(IC)1,3, a mutant of the masked strain of TMV that accumulated locally and induced no systemic symptoms, moved through vascular tissue but failed to accumulate to high levels in systemic leaves. The lack of M(IC)1,3 accumulation in systemic leaves was correlated with RNA silencing activity in this tissue through the appearance of virus-specific, approximately 25-nucleotide RNAs and the loss of fluorescence from leaves of transgenic plants expressing the 126-kDa protein fused with green fluorescent protein (GFP). The ability of TMV strains and mutants altered in the 126-kDa protein open reading frame to cause systemic symptoms was positively correlated with their ability to transiently extend expression of the 126-kDa protein:GFP fusion and transiently suppress the silencing of free GFP in transgenic N. tabacum and transgenic N. benthamiana, respectively. Suppression of GFP silencing in N. benthamiana occurred only where virus accumulated to high levels. Using agroinfiltration assays, it was determined that the 126-kDa protein alone could delay GFP silencing. Based on these results and the known synergies between TMV and other viruses, the mechanism of suppression by the 126-kDa protein is compared with those utilized by other originally characterized suppressors of RNA silencing.