Phytopathology. 2002 Jun;92(6):576-9. doi: 10.1094/PHYTO.2002.92.6.576.
ABSTRACT Plant viruses are most frequently transmitted from one host plant to another by vectors. In noncirculative vector transmission, the virus does not process through a cycle within the vector body. Instead, upon acquisition by the vector, viruses are retained in the mouth parts or the anterior gut; from there, they will be subsequently released in a new host plant. Two molecular strategies have been described for the virus-vector interaction. In the capsid strategy, the virus coat interacts directly with binding sites in the vector mouth parts, whereas an additional nonstructural protein, designated helper component (HC), is required in the helper strategy. The HC and virus particles can be acquired sequentially, and this property introduces the possibility that an HC acquired first by the vector assists the transmission of virus particles located in the same cell, in other cells, or even in other host plants probed by the vector. Such a phenomenon is here called HC-transcomplementation. Surprisingly, the existing definition of HC does not explicitly include the concept of HC-transcomplementation, and it is generally omitted in the literature in any consideration of the virus biology other than the molecular interaction with the vector. Here we propose an extended definition of HC and emphasize the concept of HC-transcomplementation that distinguishes the helper strategy from any other type of vector transmission and may have consequences at the level of the virus population genetics and evolution.
摘要 植物病毒通常通过媒介物从一个宿主植物传播到另一个宿主植物。在非循回型媒介传播中，病毒不会在媒介体内经历一个循环。相反，病毒在被媒介物获取后，会被保留在口器或前肠中；从那里，它们将在新的宿主植物中被释放。已经描述了两种用于病毒-媒介物相互作用的分子策略。在衣壳策略中，病毒衣壳直接与媒介物口器中的结合位点相互作用，而在辅助策略中需要一种额外的非结构蛋白，称为辅助成分 (HC)。HC 和病毒颗粒可以顺序获取，这种特性引入了一种可能性，即首先被媒介物获取的 HC 有助于位于同一细胞、其他细胞甚至媒介物探测到的其他宿主植物中的病毒颗粒的传播。这种现象在这里被称为 HC 转互补。令人惊讶的是，现有的 HC 定义并没有明确包括 HC 转互补的概念，并且在除了与媒介物的分子相互作用之外的任何病毒生物学考虑中，通常都被忽略。在这里，我们提出了一个扩展的 HC 定义，并强调了 HC 转互补的概念，该概念将辅助策略与任何其他类型的媒介传播区分开来，并可能对病毒群体遗传学和进化产生影响。
