摘要
为了解鸡传染性支气管炎病毒(IBV)广西流行株的遗传变异情况,应用RT-PCR方法对2004-2007年的7株广西IBV分离株的纤突蛋白S1基因、核(N)蛋白和膜(M)蛋白基因进行扩增、克隆、测序和同源性比较及系统进化分析。结果显示广西IBV分离株S1基因存在广泛的基因点突变,部分毒株出现基因插入和缺失,分离株之间氨基酸同源性为74.2%～98.7%;N基因无插入和缺失,但存在基因点突变,分离株之间氨基酸同源性为91.7%～99.3%;M基因存在点突变和插入现象,分离株之间氨基酸同源性为90.7%～98.2%。以疫苗株H120为参照,广西IBV分离株的S1、N和M基因都出现了变异,其中S1基因变异程度最大。7株广西IBV在S1、N和M基因氨基酸序列系统进化树中分别集中在2、3和3个基因群中,其中4株的S1、N和M基因分型结果不一致。结果表明广西IBV分离株的S1、N和M基因已发生变异,广西IBV存在广泛的基因突变、缺失或插入现象。研究的结果提示流行株的遗传变异可能是目前影响疫苗免疫效果的主要原因。
In order to study characteristics of genetic variations of avian infectious bronchitis virus （IBV）in Guangxi Province of China,spike S1protein,nucleocapsid（N）and membrane（M） protein genes of 7IBV strains isolated in Guangxi between 2004and 2007were amplified by re-verse transcriptase polymerase chain reaction（RT-PCR）,cloned,sequenced,compared and phy-logenetically analyzed.The results showed that many point mutations occurred within the S1 gene in all viruses and gene insertions and deletions occurred in majority of isolates.Amino acid sequence homology of S1gene among the 7IBV isolates varied from 74.2%to 98.7%.Deletion and insertion were not found in the Ngenes,but point mutations were found.Amino acid se-quence homology of Ngene among the 7IBV isolates varied from 91.7%to 99.3%.Mutations and insertions occurred in Mgenes.Amino acid sequence homology of Mgene among the 7IBV isolates varied from 90.7%to 98.2%.Majority of Guangxi IBV isolates showed variations in S1, Nand M genes comparing with H120vaccine strain and S1gene showed the biggest variation among the isolates.7IBV isolates were clustered into 2,2and 3groups in the phylogenetic trees based on the deduced amino acid sequences of S1,Nand Mgenes.The phylogenetic trees based on the Nand Mgene sequences do not follow closely the phylogenetic clustering based on the S1 gene for 4out of 7isolates.These results suggested that the variations were occurred in majority of Guangxi IBV isolates at S1,Nand Mgenes.Point mutations,insertions and deletions had contributed to the genetic diversity and emergency of IBV variants in Guangxi Province.The present results indicated that the genetic variations may provide an explanation for the reasons of vaccines can’t protect effectively against epidemic strains in the field.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2010年第9期1138-1146,共9页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
国家自然科学基金(30700599)
广西自然科学基金(桂科青0728003
桂科自0991044)
广西科技攻关项目(0993009-2)
