南瓜蚜传黄化病毒遗传多样性分析

 哈密瓜是新疆重要的经济作物之一。南瓜蚜传黄化病毒(cucurbit aphid-borne yellows virus, CABYV)是世界重要的瓜类黄化病毒,在新疆哈密瓜植株上普遍发生,严重威胁新疆哈密瓜的品质与产量。本研究从新疆阿克苏市随机采集120份哈密瓜叶片样品,经过RT-PCR检测证实38个样品为CABYV阳性,从阳性样品中分离、测序、克隆得到一个新的CABYV分离物。将该分离物与22个来自不同国家的分离物(NCBI)进行核酸和氨基酸序列一致性和系统发育分析,结果显示23个CABYV分离物根据地域差异被划分为2个不同进化群体。进一步对不同CABYV群体进行遗传多样性分析,结果表明CABYV在寄主和地理种群之间存在明显的遗传差异。选择压分析和偏离中立性检验显示CABYV种群近期可能发生了种群扩张或背景选择,并且负向选择可能是CABYV遗传变异的原因之一。本文较全面研究了CABYV的发生、危害与遗传结构及进化机制,可为新疆病毒病防治提供理论指导。

The analysis on genetic diversity of cucurbit aphid-borne yellows virus

Cantaloupe is one of the important cash crops in Xinjiang province. Cucurbit aphid-borne yellows virus (CABYV) is an important worldwide cucurbit xanthosis virus, which is widely distributed in the main growing areas of cantaloupe of Xinjiang. CABYV is serious threaten to the quality and yield of cantaloupe. In this study, a total of 120 leaf samples were randomly selected from Akesu city of Xinjiang province, among which 38 samples were positive to CABYV by RT-PCR test. A new CABYV isolate was isolated, sequenced and cloned from these positive samples. The identity and phylogenetic were analyzed based on the CP gene nucleotide sequences and amino acid sequences of 23 isolates. The results showed that the 23 CABYV isolates were divided into 2 distinct evolutionary populations according to regional differences. Further analysis of genetic diversity in different CABYV populations revealed there are significant genetic differences between CABYV host and geographic populations. Selection pressure analysis and neutrality test indicated that CABYV population may undergone population expansion or background selection recently, and negative selection may be one of the reasons for genetic variation of CABYV. The knowledge on occurrence, damage, genetic structure and evolutionary mechanism of CABYV presented in this study may be useful in the design of sustainable management strategies for controlling CABYV.