高粱红条病病原的分子鉴定

从山西高粱红条病病叶中得到一种病毒分离物,命名为GL-SX.根据甘蔗花叶病毒亚组(SCMV subgroup)外壳蛋白(CP)基因C-端和复制酶(NIb)基因C-端的保守序列设计引物,对GL-SX进行免疫捕获反转录PCR (IC-RT-PCR) 扩增,获得一条长约1.1 kb的扩增片段,扩增片段克隆后测定序列,该序列含1087个核苷酸(nt),编码362氨基酸(aa),取其中的近全长CP氨基酸序列(296 aa)与甘蔗花叶病毒(Sugarcane mosaic virus, SCMV)、玉米矮花叶病毒 (Maize dwarf mosaic virus, MDMV)、高粱花叶病毒(Sorghum mosaic virus, SrMV)和约翰逊草花叶病毒(Johnsongrass mosaic virus, JGMV) 等4种病毒的对应序列进行同源性比较,结果与SCMV的同源性最高(95.3%),而与SrMV、MDMV和JGMV等3种病毒的同源性相对较低,依次为69.3%、69.1%和55.4%.根据Potyvirus属病毒种类划分的标准,将GL-SX鉴定为SCMV.将GL-SX的近全长CP氨基酸序列与SCMV种内各分离物的对应序列进行同源性比较及构建关系树,结果显示GL-SX与SCMV-MDB具有较远缘的种内亲缘关系,而与德国的一个SCMV玉米分离物(SCVM-Hoe)及中国的两个玉米分离物(SCMV-ZJ和SCMV-BJ)具有很高的同源性.

Molecular identification of the pathogen of sorghum red stripe disease

A virus isolate GL SX was obtained from red stripe infected sorghum leaf in Taiyuan, Shanxi province. A portion of the genome of GL SX covering the C terminal region of the replicase (NIb) gene and the nearly full length region of the coat protein (CP) gene was amplified, cloned, and sequenced. It had 1087 nucleotides (nt), encoding 362 amino acids (aa). The 296 aa sequence of the nearly full length CP gene of GL SX was compared with the counterpart of Sugarcane mosaic virus (SCMV), Maize dwarf mosaic virus (MDMV), Sorghum mosaic virus (SrMV), and Johnsongrass mosaic virus (JGMV), respectively. A high identity (95.3%) was observed with SCMV,while only 69.3%?69.1%and 55.4% identity was found with SrMV, MDMV, and JGMV, respectively. According to the taxonomy rule of species and strains in Potyvirus , GL SX was identified as isolate of SCMV. The obtained CP aa sequence was then compared with the counterpart of selected isolates of SCMV, and a phylogenetic tree was constructed. It showed that GL SX was remotely related to SCMV MDB, and shared very high identity with a German maize isolate ( SCMV Hoe) and two Chinese maize isolates (SCMV ZJ, BJ).