家蚕传染性软化病病毒（桐乡株）VP1基因片段的克隆及序列分析

以首株在中国分离到的家蚕传染性软化病病毒（Bombyx mori infectious flacherie virus，BmIFV）BmIFV-CHN001基因组为模板，扩增了编码主要结构蛋白的VP1基因。克隆测序后得到VP1基因片段906 bp。该序列与已发表的日本毒株相比，核苷酸序列的相似性为99.3%，编码氨基酸的相似性为100%，证明该毒株与家蚕传染性软化病病毒日本株的同源性较高。把BmIFV-CHN001的VP1序列与同属的另外6个昆虫小RNA病毒的结构蛋白进行序列比对，构建系统发育树，对其进化关系进行了初步分析，结果显示这7种病毒具有相近的亲缘关系，而BmIFV-CHN001与蜜蜂囊雏病毒的亲缘关系最近。

Cloning and sequence analysis of VP1 gene fragment from a strain of infectious flacherie virus isolated in Zhejiang, China

BmIFV-CHN001 is the first strain of infectious flacherie virus isolated in China. In this study, the sequence of VP1 gene fragment coding the main structural protein of BmIFV-CHN001 was amplified. Subsequent cloning and sequencing showed that the sequence fragment was 906 nucleotides in length. Comparison with the VP1 gene of the published Japanese strain indicated that the nucleotide sequence similarity was 99.3% while the amino acid sequence similarity was up to 100%,suggesting that BmIFV-CHN001 was highly homologous to the Japanese strain. Amino acid sequences alignment was performed based on the main structural proteins from BmIFV-CHN001 and other six viruses belonging to the same genus,Iflavirus. A phylogenetic tree was constructed. The results showed that there were close relationships among the seven viruses, while BmIFV-CHN001 had the closest relationship with the sacbrood virus of the honey bee.