广西家蚕核型多角体病毒株gp64基因 克隆与序列分析
Cloning and sequence analysis of gp64 gene in Bombyx mori nucleopolyhedrovirus Guangxi isolates
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摘要: 目的了解广西家蚕核型多角体病毒(Bombyxmori nucleopolyhedrovirus,BmNPV)毒株gp64基因的保守性,并掌握其具体的突变位点,为研究核型多角体病毒(NPV)种内的微进化模式提供参考依据.方法对广西不同桑蚕产区的19株BmNPV毒株进行gp64基因克隆与测序,分析完整开放阅读框(ORF)序列的同源性和单核苷酸多态性,并构建基于gp64基因的遗传进化树.结果广西BmNPV毒株的gp64基因ORF序列不一致,存在1590、1593和1599 nt三种类型,是由于第94~96位缺失GCG或第97~102位插入GCGCCG所致,且插入核苷酸突变仅在广西BmNPV毒株中出现.仅GXSL毒株与T3毒株的核苷酸及其推导氨基酸序列同源性均达100.0%,其余18株毒株与T3毒株的核苷酸序列同源性在98.5%~99.2%,其推导氨基酸序列同源性在98.7%~99.6%.19株广西BmNPV毒株被分为两个亚群(cladeⅠ和cladeⅡ),其中11株独立形成cladeⅡ,7株独立形成cladeⅠ中的一个亚群;广西毒株在多个位点出现同义核苷酸突变,呈一定的规律性.结论广西BmNPV毒株的gp64基因具有遗传多样性,在遗传进化上较独立,插入突变显示出地域特点.Abstract: ObjectiveThis research aimed to understand gp64 gene conservation of Bombyx mori nucleopolyhedrovirus (BmNPV) Guangxi isolates and master the specific site of mutation, which could provide reference for study of intraspecific microevolution pattern of nucleopolyhedrovirus(NPV). MethodThe gp64 genes of 19 BmNPV strains collected from dif-ferent sericultural areas in Guangxi were cloned and sequenced. Homology and the mononucleotide polymorphisms of gp64 complete open reading frame(ORF) were analyzed, and phylogenetic tree of gp64 gene was established. ResultThe gp64 gene ORF sequences of Guangxi BmNPV strains were not consistent, showing three types as 1590 nt, 1593 nt and 1599 nt. The diversities were caused by GCG deletion in position 94-96, and GCGCCG insertion in position 97-102. inser-tion mutations of nucleotide only happened in Guangxi BmNPV strains. Only GXSL strain shared 100.0%homologies in nu-cleotide and deduced amino acid sequence with T3 strain. The other 18 strains shared 98.5%-99.2% homology in nu-cleotide sequence and 98.7%-99.6% homology in deduced amino acid sequence with T3 strain. All 19 Guangxi BmNPV strains were separated into two clades(clade Ⅰand clade Ⅱ). Among them, 11 strains were included in clade Ⅱ sep-arately and 7 strains were included in a sub-clade of cladeⅠ. Synonymous substitutions occurred in several positions of gp64 genes from Guangxi BmNPV strains, showing certain regularity.ConclusionThe gp64 genes of Guangxi BmNPV strains em-bodies genetic diversity and independent genetic evolution. The insertion mutation indicates territorial characteristic.