玉米矮花叶病毒分离物基因组克隆及多样性分析

Genome Cloning and Genetic Diversity of Sugercan mosaic virus

玉米是重要的粮食和经济作物,在国民经济中占有重要地位。玉米矮花叶病毒(Sugercan mosaic virus,SCMV)广泛分布在世界各玉米主产区,严重威胁玉米的安全生产。系统研究SCMV的发生危害、遗传结构与进化机制,对病毒病的防治具有重要意义。从山西省4个玉米主产区采集122个玉米叶片样品(2015年62份,2016年60份)。经RT-PCR检测证实36个样品(2015年20个样品,2016年16个样品)为SCMV阳性,且广泛分布于山西省玉米各个产区。从这些阳性样品中分离、测序、克隆得到了一个新的SCMV分离物,该分离物(包括5’-UTR和3’-UTR端)基因组全长9 539 bp,编码3 063个氨基酸。该分离物与26个SCMV分离物(NCBI)进行一致率、系统发育分析表明SCMV存在较大遗传变异,27个分离物被划分为3个与地理位置无明显相关性的不同进化群体。选择压力分析表明,负向选择可能是SCMV遗传变异的原因之一。对变异位点统计分析发现,该结果将为评估SCMV在中国的流行病学特征奠定基础,有助于SCMV的长期可持续防控策略的制定。

Maize is an important food and economic crop, which plays an important role in the national economy. Sugercan mosaic virus widely distributed in the main maize producing areas in the world, and it is a great threat for the maize production. For controling SCMV, it is necessary to systematically study the damage, genetic structure and evolution mechanism. This study collected 122 maize leaf samples (62 samples in 2015 and 60 samples in 2016) from four maize producing areas in Shanxi province. By RT-PCR, 36 samples (20 in 2015 and 16 in 2016) were proved to be positive for SCMV. One new SCMV strain was isolated and sequenced from these positive samples. It was found that the genome of this isolate was 9 539 bp including 5′-UTR and 3′-UTR region and encoded 3 063 aa. The identity and phylogenetic analysis with 26 isolates reported online NCBI were carried out, it was found the 27 isolates were divided into 3 different evolutionary populations based on the whole-genome. The results of this study provided a basis for assessing the epidemiological characteristics of SCMV in China and contribute to the formulation of long-term sustainable prevention and control strategies for SCMV.