黄瓜花叶病毒亚组Ⅰ和Ⅱ分离物外壳蛋白基因的序列分析与比较

COAT PROTEIN GENE SEQUENCE ANALYSIS AND COMPARISON OF CUCUMBER MOSAIC VIRUS SUBGROUP Ⅰ AND Ⅱ ISOLATES IN CHINA

对我国分离的经生物学和血清学鉴定为黄瓜花叶病毒（ＣＭＶ）亚组Ⅰ和Ⅱ的各一分离物（ＧＢ、ＸＢ）的外壳蛋白（ＣＰ）基因进行了序列分析和比较。以提纯病毒ＲＮＡ为模板，进行逆转录及ＰＣＲ扩增，并通过常规基因克隆方法得到插入ＣＰ基因片段的重组克隆。对插入ＧＢ和ＸＢ两个分离物ＣＰ基因片段的重组克隆进行全序列测定，结果表明重组克隆序列长分别为７７７ｂｐ和７９２ｂｐ，均只含一个开放读框（ＯＲＦ），长度为６５７ｎｔ，可编码２１８个氨基酸；两个分离物的ＣＰ基因核苷酸序列同源率为７７５％，氨基酸序列同源率为８２６％。与我国已报道的７个ＣＭＶ分离物的ＣＰ基因序列比较，分离物ＧＢ的同源率为９１３％～９７３％，分离物ＸＢ的同源率为７６６％～７８４％。与国际上已报道部分ＣＭＶ株系的ＣＰ基因序列相比较，分离物ＧＢ与亚组Ⅰ株系有更密切的亲缘关系，而分离物ＸＢ则与亚组Ⅱ株系的亲缘关系更密切。

Nucleotide sequence analysis and comparison of the coat protein(CP) genes of two isolates(GB and XB) belonging to different cucumber mosaic virus(CMV) subgroups determined by biology and serology were carried out. The results revealed that there was an open reading frame of 657 nucleotides which could encode the protein of 218 amino acids of each isolate. GB and XB shared 77.5% nucleotide and 82.6% amino acid sequence homology. The nucleotide sequence of GB shared 91.3%～97.3% homology with seven CMV isolates previously reported from China, while XB only shared 76.6%～78.4%. GB was found to be more closely related with CMV subgroup Ⅰ, while XB was with subgroup Ⅱwhen their CP gene sequences were compared to partly known CMV CP gene sequences selected from the GenBank.