三株鸽新城疫病毒新疆分离株F基因序列分析及遗传起源探讨

Genetic ancestry and sequencing of F gene segments of three pigeon NDV strains isolated from Xinjiang

用RT-PCR方法从3株鸽新城疫病毒(Newcastle disease virus,NDV)新疆分离株中扩增出F基因裂解位点前后482 bp片段,将其克隆至pGEM-T Easy载体并进行核苷酸序列测定。用DNAStar软件对分离株的F基因片段与国内外相关的NDV参考株进行比较,结果表明3个分离株之间核苷酸及氨基酸序列同源性分别为99.6%～99.8%和99.4%～100.0%,与其它鸽源NDV F基因相应部分核苷酸及氨基酸序列同源性分别为89.4%～98.1%和90.6%～98.1%,而与国内代表性弱毒疫苗株LaSota毒株和NDV强毒株F48E9的核苷酸及氨基酸序列同源性分别为86.3%和87.6%及90.0%和92.5%。遗传发育进化树分析表明3个分离株属NDV基因型Ⅵ,与法国株(Pigeon-France-99)、意大利株(Pigeon-Italy-00)形成同一细分支,其核苷酸同源性为97.9%～98.1%,F基因的裂解位点氨基酸序列都为112R-R-Q-K-R-F117,是典型的强毒株共有序列,新疆鸽流行株与欧洲鸽流行株有很近的遗传亲缘关系,为同一基因亚型。对疫病流行时间、新疆独特的地理位置和病毒基因遗传衍化关系等方面进行综合考虑与分析,2000年开始在新疆地区流行的鸽NDV和欧洲国家上述流行株具有共同的遗传起源,推测通过从国外引种或者候鸟迁移等途径传播的可能性较大。

The F gene fragments of 482 bp were amplified by RT-PCR from 3 pigeon Newcastle disease virus （NDV） strains isolated from Xinjiang. The PCR fragments were cloned into pGEM-T Easy vector and sequenced. Compared with other F genes of NDV strains, the 3 NDV strains shared nucleotide and amino acid identities of 99.6 % to 99.8 % and 99.4 % to 100.0 % respectively with the NDV reference strains from GenBank; 89.4 % to 98.1% and 90.6 % to 98.1% respectively with other pigeon NDV reference strains; and 86.3 % to 87.6 % and 90.0 % to 92.5 % respectively with the vaccine strain LaSota and high virulent strain F48E9, The three NDV strains were grouped into genotype Ⅵ of NDV by the phylogenetic tree analysis and aligned into the main sub-branch with Pigeon-France-99 strain and the Pigeon-Italy-00 strain. The cleavage site of the F gene possessed a typical virulent strain＇s mutual sequence of ^112R-R-Q-K-R-F^117. There was a close genetic relationship between Xinjiang isolates and European epidemic strains that all belonged to the same gene subtype. It is proposed that the epidemic strain of pigeon Newcastle disease in Xinjiang since 2000 may have originated from a common genetic ancestor of foreign strains from European countries, such as France and Italy.