Molecular evolution of Turnip mosaic virus:: evidence of host adaptation, genetic recombination and geographical spread
Molecular evolution of Turnip mosaic virus:: evidence of host adaptation, genetic recombination and geographical spread
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DOI：
10.1099/0022-1317-83-6-1511
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发表时间：
2002-06-01
影响因子：
3.8
通讯作者：
Gibbs, A
中科院分区：
文献类型：
--
作者：
Ohshima, K;Yamaguchi, Y;Gibbs, A
芜菁花叶病毒（Turnip mosaic virus，TuMV）是马铃薯Y病毒属的一种病毒，在世界范围内广泛发生。从世界各地收集了76个TuMV分离物，大多数来自芸苔属和萝卜属作物，但也来自几个非芸苔属物种。寄主试验将分离物分为两个致病型中的一个或另一个;芸苔属（B）和萝卜属（BR）。测定了分离株的第一蛋白（P1）和外壳蛋白（CP）基因的核苷酸序列。十分之一的菌株被发现有异常和可变的系统发育关系作为重组的结果。许多菌株的P1基因5 '端300 nt也是可变的，并且在遗传学上是异常的，而CP基因3'端380 nt大部分是保守的。通过相邻连接、最大似然和最大简约方法从非重组序列的两个基因的剩余信息部分计算的树非常相似，因此将序列的这些部分连接起来，并从所得的1150 nt计算树。分离物分为四个一致的组;只有这些组之间的关系和与外群的关系不同。8个B致病型分离物的“basal-B”簇是最易变的，不是单系的，并且来自欧亚大陆西南部和中部的芸苔属和非芸苔属。最接近它，并形成一个单系亚组，它在大多数树木，同样可变的，是'基础BR'组的8个BR致病型欧亚分离株。第三和最少的变量组，“亚洲BR”组，是22 BR致病型菌株，所有从芸苔属，主要是萝卜属，和所有来自东亚主要是日本。第四组36个菌株，“世界-B”组，来自各大洲，大多数分离自芸苔属，大多数为B致病型。在对这些树的几种可能的解释中，最简单的解释是TuMV起源于欧洲，就像它的芸苔属宿主一样，并传播到世界其他地区，而BR致病型最近在东亚进化。
Turnip mosaic virus (TuMV), a species of the genus Potyvirus, occurs worldwide. Seventy-six isolates of TuMV were collected from around the world, mostly from Brassica and Raphanus crops, but also from several non-brassica species. Host tests grouped the isolates into one or other of two pathotypes; Brassica (B) and Brassica-Raphanus (BR). The nucleotide sequences of the first protein (P 1) and coat protein (CP) genes of the isolates were determined. One-tenth of the isolates were found to have anomalous and variable phylogenetic relationships as a result of recombination. The 5-terminal 300 nt of the P1 gene of many isolates was also variable and phylogenetically anomalous, whereas the 380 nt 3' terminus of the CP gene was mostly conserved. Trees calculated from the remaining informative parts of the two genes of the non-recombinant sequences by neighbour-joining, maximum-likelihood and maximum-parsimony methods were closely similar, and so these parts of the sequences were concatenated and trees calculated from the resulting 1150 nt. The isolates fell into four consistent groups; only the relationships of these groups with one another and with the outgroup differed. The 'basal-B' cluster of eight B-pathotype isolates was most variable, was not monophyletic, and came from both brassicas and non-brassicas from southwest and central Eurasia. Closest to it, and forming a monophyletic subgroup of it in most trees, and similarly variable, was the 'basal-BR' group of eight BR pathotype Eurasian isolates. The third and least variable group, the 'Asian-BR' group, was of 22 BR-pathotype isolates, all from brassicas, mostly Raphanus, and all from east Asia mostly Japan. The fourth group of 36 isolates, the 'world-B' group, was from all continents, most were isolated from brassicas and most were of the B-pathotype. The simplest of several possible interpretations of the trees is that TuMV originated, like its brassica hosts, in Europe and spread to the other parts of the world, and that the BR pathotype has recently evolved in east Asia.