甘蔗线条花叶病毒HC-Pro基因的分子变异分析

摘要

为了解析甘蔗线条花叶病毒Sugarcane streak mosaic virus (SCSMV)不同分离物HC-Pro基因的分子变异规律,本研究利用RT-PCR法扩增获得SCSMV HC-Pro基因的序列,通过生物信息学分析,分别从重组、系统发生、选择压力等方面研究SCSMV HC-Pro基因的分子变异特征.共测定了44条SCSMV HC-Pro基因序列,相似性最低值为70％;HC-Pro基因重组频率较低,仅发现3个重组位点,其中一个系首次报道;与先前报道相比,部分新测定云南蔗区的SCSMV分离物在HC-Pro基因上形成一个新组—第Ⅲ组;HC-Pro基因处于很强的负选择压力作用,未发现正向选择作用位点.本研究结果进一步证明SCSMV HC-Pro基因具有高度的遗传多样性.%The objective of this study is to assess the molecular evolution and divergence of SCSMV according to HC-Pro gene sequences.The HC-Pro gene sequences of SCSMV were obtained by RT-PCR,and analyzed by bioinformatic software,in aspect of recombination,phylogenetics,selection,demography,and gene flow.In the present study,44 HC-Pro gene sequences were determined with a 70％ lowest similarity;only one novel recombination site together with two previous reported sites were found in HC-Pro gene,suggesting that infrequent recombination events were distributed in this gene of SCSMV;one novel lineage (lineage Ⅲ) clustered by SCSMV sequences determined here was found;strong purifying selection was found in the HC-Pro gene of SCSMV.Our genetic study further indicates that the HC-Pro gene showed high genetic diversity in the genome of SCSMV.