黄瓜花叶病毒(CMV)2个山西分离物CP序列测定及亚组分类分析

 在生物学检测的基础上,利用酶联免疫检测、非序列依赖性PCR(sequence-independent amp-lification, SIA)对感病番茄进行分子鉴定,表现卷叶和花叶症状的番茄均被黄瓜花叶病毒(Cucumber mosaic virus,CMV)侵染,分离物分别命名为SXFQ(GenBank登录号为JX993914)和FQ(GenBank登录号为JX993912)。为明确其分类地位,对二者外壳蛋白(coat protein, CP)进行克隆和测序分析。应用DNAMAN软件对本课题组前期检测的7个CMV山西分离物、SXFQ、FQ以及其他3个CMV典型分离物CP序列进行比较分析,发现核苷酸和氨基酸序列最大相似性分别为77.1%~100%和81.6%~100%。氨基酸序列系统进化分析表明,9个CMV山西分离物属于CMV亚组I B的2个分支,其中在指示植物上表现较强症状的SXFQ与其他5个分离物为一分支,在指示植物上表现较弱症状的FQ与其他2个分离物为另一分支。对9个山西分离物CP进行亚组分类分析,结果表明其理化性质、稳定性、疏水性与预测结果相近,2个分支的分离物分别出现相近的氨基酸变异和蛋白结构,存在一定规律性。

Sequence and subgroup analysis of two new isolates of Cucumber mosaic virus (CMV) in Shanxi

To identify the viruses that may cause Lycopersicon esculentum malformations wrinkling disease,we used biological, serological and molecular methods. Results revealed that the virus associated with this disease was Cucumber mosaic virus (CMV). Two isolates were identified as SXFQ (GenBank accession number: JX993914) and FQ (GenBank accession number: JX993912). The identities of nucleotide and deduced amino acid sequences of CP gene among 9 CMV isolates of our research group and 3 other typical CMV isolates ranged from 77.1 % to 100 % and 81.6 % to 100 %, respectively. Phylogenetic trees based on the aa sequences showed that 9 CMV isolates of our laboratory belong to two branches of CMV subgroup Ⅰ B. SXFQ and other 5 isolates belong to a branch which exhibits strong symptoms on the indicator plant. FQ and other 2 isolates belong to another branch which exhibits weak symptoms on the indicator plant. We analysed the subgroup of 9 Shanxi isolates CP. The results showed that the physical and chemical properties, stability and hydrophobicity were similar. The two branches showed similar amino acid variation and protein structure. It indicates that CMV isolates of the same branch of CMV subgroup Ⅰ B had some nearly certain regularity.