Tomimura K, Gibbs A J, Jenner C E, Walsh J A, Ohshima K
Laboratory of Plant Virology, Faculty of Agriculture, Saga University, Saga 840-8502, Japan.
Mol Ecol. 2003 Aug;12(8):2099-111. doi: 10.1046/j.1365-294x.2003.01881.x.
The genomes of a representative world-wide collection of 32 Turnip mosaic virus (TuMV) isolates were sequenced and these, together with six previously reported sequences, were analysed. At least one-fifth of the sequences were recombinant. In phylogenetic analyses, using genomic sequences of Japanese yam mosaic virus as an outgroup, the TuMV sequences that did not show clear recombination formed a monophyletic group with four well-supported lineages. These groupings correlated with differences in pathogenicity and provenance; the sister group to all others was of Eurasian B-strain isolates from nonbrassicas, and probably represents the ancestral TuMV population, and the most recently 'emerged' branch of the population was probably that of the BR-strain isolates found only in east Asia. Eight isolates, all from east Asia, were clear recombinants, probably the progeny of recent recombination events, whereas a similar number, from other parts of the world, were seemingly older recombinants. This difference indicates that the presence of clear recombinants in a subpopulation may be a molecular signature of a recent 'emergence'.
对来自世界各地的32种芜菁花叶病毒（TuMV）分离株的基因组进行了测序，并将这些序列与之前报道的6个序列一起进行了分析。至少五分之一的序列是重组的。在系统发育分析中，以日本山药花叶病毒的基因组序列作为外群，未显示明显重组的TuMV序列形成了一个单系群，有四个得到充分支持的谱系。这些分组与致病性和来源的差异相关；所有其他谱系的姐妹群是来自非十字花科植物的欧亚B株分离株，可能代表了TuMV的祖先群体，而该群体中最近“出现”的分支可能是仅在东亚发现的BR株分离株。来自东亚的8个分离株是明显的重组体，可能是近期重组事件的后代，而来自世界其他地区的数量相近的分离株似乎是较古老的重组体。这种差异表明，亚群中明显重组体的存在可能是近期“出现”的分子特征。
