甘蔗花叶病毒福州分离物全基因组克隆及种群分析

Genome cloning of two Sugarcane mosaic virus isolates from Fuzhou and phylogenetic analysis of SCMV

为丰富甘蔗花叶病毒(Sugarcane mosaic virus,SCMV)种群信息,探索SCMV种群结构,本研究运用RT-PCR方法克隆了采自福州的2个SCMV分离物(分别命名为FZ-C1和FZ-C2)的全基因组,结合已公布的18个SCMV分离物的全基因组序列,利用MEGA 4.1和Simplot软件对SCMV的种群结构进行了分析。结果显示,FZ-C1和FZ-C2全长分别为9 570nt和9 573 nt,均包含一个9 189 nt的开放阅读框,编码长度为3 063个氨基酸的多聚蛋白。这2个分离物与SCM V-A株系的相似性最高,酶切位点也与SCMV-A株系的基本一致。系统发育进化分析表明,SCMV可以分为3组,分别命名为SSGⅠ、Ⅱ、Ⅲ。SSGⅠ来源于玉米(Zea mays),SSGⅡ和SSGⅢ来源于甘蔗(Saccharum spp.hybrid),其中SSGⅢ主要来源于果蔗。FZ分离物聚在SSGⅡ组内。研究结果丰富了SCMV全基因组序列信息,有助于全面了解SCMV种群的遗传进化关系。

This study was aimed at understanding the phylogenesis of Sugarcane mosaic virus （SCMV）. The complete genomes of two SCMV isolates obtained at Fuzhou, designated as FZ-C1 and FZ-C2, respectively, were cloned in this study. Based on the genome sequences of the new SCMV isolates and published 18 SCMV isolates, the genetic diversity and population structure of SCMV were analyzed using MEGA 4.1 and Simplot softwares. Results showed that the genome of FZ-C1 contains 9 570 nucleotides, while FZ-C2 contains 9 573 nu- cleotides. Both FZ-C1 and FZ-C2 have a single open reading frame of 9 189 nt in length and encode a polypro- tein containing 3 1363 amino acids. FZ-C1 and FZ-C2 shared high similarity with SCMV-A at both nucleotide and amino acid level, as well as the restriction sites. Phylogenetic analysis showed that SCMV strains could be divi- ded into three groups： SSG I, Ⅱ and Ⅲ. Strains in SSG I were mainly isolated from Zea mays, while SSG Ⅱ and SSG Ⅲ were from sugarcane, especially the SSG Ⅲ that were primarily isolated from chewing cane. Two FZ iso- lates were grouped into the SSG Ⅱ. Our work enriched the whole genome sequence information of SCMV and shed light on the phylogenesis of SCMV.