Mohammadi Musa, Gibbs Adrian J, Hosseini Ahmad, Hosseini Samin
Department of Plant Protection, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
Emeritus Faculty, Australian National University, Canberra, Australia.
Virus Genes. 2018 Apr;54(2):272-279. doi: 10.1007/s11262-018-1533-8. Epub 2018 Jan 12.
Beet mosaic virus (BtMV), the only Potyvirus known to infect sugar beet, occurs worldwide in beet crops. The full genome sequencing of a BtMV isolate from Iran (Ir-VRU), enabled us to better understand the evolutionary history of this virus. Selection analysis suggested that BtMV evolution is mainly under negative selection but its strength varies in different proteins with the multifunctional proteins under strongest selection. Recombination has played a major role in the evolution of the BtMVs; only the Ir-VRU and USA isolates show no evidence of recombination. The ML phylogenies of BtMVs from coat protein and full sequences were completely congruent. The primary divergence of the BtMV phylogeny is into USA and Eurasian lineages, and the latter then divides to form a cluster only found in Iran, and a sister cluster that includes all the European and Chinese isolates. A simple patristic dating method estimated that the primary divergence of the BtMV population was only 360 (range 260-490) years ago, suggesting an emergence during the development of sugar beet as a crop over the past three centuries rather than with the use of leaf beet as a vegetable for at least 2000 years.
甜菜花叶病毒（BtMV）是已知唯一能感染甜菜的马铃薯Y病毒属病毒，在全球范围内的甜菜作物中均有发生。对一株来自伊朗的BtMV分离株（Ir-VRU）进行全基因组测序，使我们能够更好地了解这种病毒的进化史。选择分析表明，BtMV的进化主要受负选择影响，但其强度在不同蛋白质中有所不同，多功能蛋白质受到的选择最强。重组在BtMV的进化中起了主要作用；只有Ir-VRU和美国分离株没有重组证据。基于外壳蛋白和全序列构建的BtMV最大似然系统发育树完全一致。BtMV系统发育树的主要分化是分为美国谱系和欧亚谱系，后者随后又分化形成一个仅在伊朗发现的簇，以及一个包含所有欧洲和中国分离株的姐妹簇。一种简单的祖先定年方法估计，BtMV群体的主要分化仅发生在360（范围为260 - 490）年前，这表明该病毒是在过去三个世纪甜菜作为一种作物发展过程中出现的，而不是在至少2000年来一直作为蔬菜的叶用甜菜使用过程中出现的。
