Qu Feng, Morris T Jack
School of Biological Sciences, University of Nebraska-Lincoln, 68588-0118, USA.
Mol Plant Microbe Interact. 2002 Mar;15(3):193-202. doi: 10.1094/MPMI.2002.15.3.193.
Tomato bushy stunt virus (TBSV) is one of few RNA plant viruses capable of moving systemically in some hosts in the absence of coat protein (CP). TBSV also encodes another protein (p19) that is not required for systemic movement but functions as a symptom determinant in Nicotiana benthamiana. Here, the role of both CP and p19 in the systemic spread has been reevaluated by utilizing transgenic N. benthamiana plants expressing the movement protein (MP) of Red clover necrotic mosaic virus and chimeric TBSV mutants that express CP of Turnip crinkle virus. Through careful examination of the infection phenotype of a series of mutants with changes in the CP and p19 genes, we demonstrate that both of these genes are required for efficient systemic invasion of TBSV in N. benthamiana. The CP likely enables efficient viral unloading from the vascular system in the form of assembled virions, whereas p19 enhances systemic infection by suppressing the virus-induced gene silencing.
番茄丛矮病毒（TBSV）是少数几种在没有衣壳蛋白（CP）的情况下仍能在某些宿主中进行系统移动的RNA植物病毒之一。TBSV还编码另一种蛋白（p19），该蛋白对于系统移动并非必需，但在本氏烟草中作为症状决定因素发挥作用。在此，通过利用表达红三叶草坏死花叶病毒移动蛋白（MP）的转基因本氏烟草植物以及表达芜菁皱缩病毒CP的嵌合TBSV突变体，对CP和p19在系统传播中的作用进行了重新评估。通过仔细检查一系列CP和p19基因发生变化的突变体的感染表型，我们证明这两个基因对于TBSV在本氏烟草中的有效系统侵染都是必需的。CP可能以组装好的病毒粒子的形式使病毒从维管系统中有效卸载，而p19则通过抑制病毒诱导的基因沉默来增强系统感染。
