Chapman S, Kavanagh T, Baulcombe D
Sainsbury Laboratory, Norwich Research Park, UK.
Plant J. 1992 Jul;2(4):549-57. doi: 10.1046/j.1365-313x.1992.t01-24-00999.x.
The suitability of potato virus X (PVX) as a gene vector in plants was tested by analysis of two viral constructs. In the first, the GUS gene of Escherichia coli was substituted for the viral coat protein gene. In the second, GUS was added into the viral genome coupled to a duplicated copy of the viral promoter for the coat protein mRNA. The viral construct with the substituted coat protein gene accumulated poorly in inoculated protoplasts and failed to spread from the site of infection in plants. These results suggest a role for the viral coat protein in key stages of the viral infection cycle and show that gene replacement constructs are not suitable for the production of PVX-based gene vector. The construct with GUS coupled to the duplicated promoter for coat protein mRNA also accumulated less well in protoplasts than the unmodified PVX, but did infect systemically and directed high level synthesis of GUS in inoculated and systemically infected tissue. Although there was some genome instability in the PVX construct, much of the viral RNA in the systemically infected tissue had retained the foreign gene insertion, especially in infected Nicotiana clevelandii plants. These data point to a general utility of PVX as a vector for unregulated gene expression in plants.
通过对两种病毒构建体的分析，测试了马铃薯X病毒（PVX）作为植物基因载体的适用性。在第一种构建体中，用大肠杆菌的GUS基因取代了病毒外壳蛋白基因。在第二种构建体中，将GUS添加到与病毒外壳蛋白mRNA的重复启动子相连的病毒基因组中。带有取代外壳蛋白基因的病毒构建体在接种的原生质体中积累不佳，并且未能从植物中的感染部位扩散。这些结果表明病毒外壳蛋白在病毒感染周期的关键阶段发挥作用，并表明基因替换构建体不适用于生产基于PVX的基因载体。与外壳蛋白mRNA的重复启动子相连的GUS构建体在原生质体中的积累也不如未修饰的PVX，但确实能进行系统感染，并在接种和系统感染的组织中指导GUS的高水平合成。尽管PVX构建体存在一些基因组不稳定性，但系统感染组织中的许多病毒RNA保留了外源基因插入，特别是在感染的克利夫兰烟草植物中。这些数据表明PVX作为植物中不受调控的基因表达载体具有普遍用途。
