Harrison B D, Robinson D J
Scottish Crop Research Institute, Invergowrie, Dundee, U.K.
Philos Trans R Soc Lond B Biol Sci. 1988 Oct 31;321(1207):447-62. doi: 10.1098/rstb.1988.0102.
Patterns of variation are examined in four groups of plant viruses, with special reference to their particle proteins and to changes in vector transmissibility and specificity. In the nepoviruses and potyviruses, non-circulative transmission, by nematodes and aphids respectively, seems dependent on structural features on the surface of the virus particles. The N-terminal part of the particle protein may play the key role in potyviruses. Similarly in the luteoviruses, and possibly in the geminiviruses, specificity of circulative transmission by aphids, whiteflies and leafhoppers is linked to the antigenic specificity of the virus particles. Among naturally occurring isolates of the same virus, variation seems often to be discontinuous, and is predominantly of two sorts. Minor variations, characterized by loss of an epitope or substitutions of a few amino acids, can be associated with loss of transmissibility in luteoviruses and potyviruses, or have no effect. Major variations are associated with differences in vector specificity and seem likely to involve radical genetic changes that have evolved over long periods. The adaptation of virus particle proteins for transmission by vectors probably results in conservation of the genes that encode them, and in greater conservation of some parts of these genes than of others.
研究了四类植物病毒的变异模式，特别关注其病毒粒子蛋白以及介体传播性和特异性的变化。在线虫传多面体病毒和马铃薯Y病毒中，分别由线虫和蚜虫进行的非循环传播似乎取决于病毒粒子表面的结构特征。病毒粒子蛋白的N端部分可能在马铃薯Y病毒中起关键作用。同样，在黄症病毒中，可能还有双生病毒中，由蚜虫、粉虱和叶蝉进行的循环传播特异性与病毒粒子的抗原特异性相关。在同一病毒的自然分离株中，变异似乎常常是不连续的，主要有两种类型。以表位丧失或少数氨基酸替代为特征的微小变异，可能与黄症病毒和马铃薯Y病毒传播性丧失有关，或者没有影响。重大变异与介体特异性差异有关，似乎可能涉及长期进化而来的根本性遗传变化。病毒粒子蛋白适应介体传播可能导致编码这些蛋白的基因得到保守，并且这些基因的某些部分比其他部分得到更大程度的保守。
