河南不同临床型鸡支气管炎病毒流行毒株的分离鉴定及其S1基因变异分析

Isolation,identification and variation analysis of S1 gene of current isolates of avian infectious bronchitis virus in Henan province

经鸡胚接种、RT-PCR、气管环培养等方法从河南地区发病鸡群中分离、鉴定出2株鸡传染性支气管炎病毒(Infectious bronchitic virus,IBV),分别命名为HN/HL株和HN/SG株。应用RT-PCR方法对尿囊液中HN/HL株和HN/SG株以及本室保存的H120株的S1基因全序列进行了扩增,并对其进行克隆测序。结果显示,3株IBV目的片段全长分别为1828、1825、1819bp,3个序列相互之间存在多位点的变异,同时存在插入和缺失现象;对推导的氨基酸序列进行分析表明,HN/HL株S蛋白裂解识别位点序列为HRRRR,而HN/SG株和H120株S蛋白裂解识别位点同为RRFRR。将测序结果同GenBank上登录的其他IBVS1基因相比较,发现本试验的HN/HL株与疫苗H120株的同源性仅为78.1%,HN/SG株与H120株的同源性仅为81.1%,而HN/HL株与HN/SG株的同源性为87.9%。同源性及遗传进化分析还发现,已报道的腺胃型ZJ971株和QX株在分子水平上应该分别属于呼吸型和肾型IBV。

Two infectious bronchitis viruses （IBV）,respectively designated HN/HL strain and HN/SG strain,were isolated and identified by inoculating into chicken embryos and RT-PCR.Partial spike gene of HN/HL strain,HN/SG strain and H120 strain were amplified and sequenced.The results of sequencing showed that the sizes of three segments were 1 828,1 825 and 1 819 bp,respectively.There were great mutations in many sites among three sequences,insertion and deletion were existed simultaneously; The analysis of deduced amino acid sequences showed that S protein cleavage sites of HN/HL strain,HN/SG strain and H120 strain were H-R-R-R-R,R-R-F-R-R and R-R-F-R-R,respectively; These sequences were compared with other spike gene sequences on GenBank,the result showed that the spike gene of HN/HL strain had 78.1% identity to vaccine H120 strain.Simultaneously,HN/SG strain had 81.1% identity to H120 strain,and the homology between HN/HL strain and HN/SG strain is 87.9%.The result of genetic evolution analysis showed that proventriculus-type ZJ971 strain and QX strain actually belong to Nephropathogenic and respiratory -type IBV.