3株传染性支气管炎病毒蛋鸡源河南株的S1基因序列分析

Sequence Analysis of S1 Gene of Three Avian Infectious Bronchitis Virus Strains Isolated from Layer of Henan Province

为了解河南省致蛋鸡产蛋量下降的传染性支气管炎病毒(IBV)的流行特征,从河南南阳、信阳和安阳等市的发病鸡场中鉴定出3株IBV,分别命名为CK/CH/HN/NY1206/2017、CK/CH/HN/XY911/2017和CK/CH/HN/AY119/2018,并应用RT-PCR技术对3个IBV分离株的S1基因进行扩增与序列分析。结果显示,3个IBV分离株S1基因全长都为1617nt,编码539aa,并且都属于基因型4/91(CHⅡ);CK/CH/HN/NY1206/2017株S1基因裂解位点为RRSRR,CK/CH/HN/XY911/2017株S1基因裂解位点为RRSRR,CK/CH/HN/AY119/2018株S1基因裂解位点为RRFRR;3个分离株间核苷酸序列及其推导的氨基酸序列具有较高同源性,与位于同一基因型的参考毒株间同源性较高,与我国使用的Mass型常规疫苗H120和H52株的核苷酸和氨基酸同源性最低,分别仅为78.3%~78.4%和74.8%~75.4%,与4/91(CHⅡ)型疫苗4/91株的核苷酸和氨基酸同源性较高,分别达到94.7%~99.3%和93.9%~98.1%。综上,河南省致蛋鸡产蛋量下降的IBV流行株基因型相对统一,使用4/91(CHⅡ)型疫苗应可提高蛋鸡抗IBV的效率。

To understand the epidemic characteristics of infectious bronchitis virus (IBV) causing egg production decrease of laying hens in Henan province,this study identified three IBV isolates from chicken farms in Nanyang,Xinyang and Anyang,Henan province,which were named CK/CH/HN/NY1206/2017,CK/CH/HN/XY911/2017 and CK/CH/HN/AY119/2018,respectively.The S1 genes of these IBV isolates were amplified by RT-PCR and sequenced finally.The results showed that all S1 genes of the three IBV isolates were 1 617 nt,encoding 539 aa,and all belonged to genotype 4/91(CHⅡ).The cleavage sites of S 1 gene in CK/CH/HN/NY1206/2017,CK/CH/HN/XY911/2017 and CK/CH/HN/AY119/2018 strains were RRSRR,RRSRR and RRFRR,respectively.The nucleotide sequences of three isolates and their derived amino acid sequences were homologous,and homology was higher with reference strains belonged to the same genotype.The homologies of nucleotides and amino acids between three isolates and conventional vaccines H120 and H52 of Mass type used in China were the lowest with 78.3% to 78.4% and 74.8% to 75.4% only,and the homologies with vaccines 4/91 of 4/91(CHⅡ) type were higher,reaching 94.7% to 99.3% and 93.9% to 98.1%.This study showed that the IBV epidemic genotypes causing egg production decline of laying hens in Henan province were relatively uniform,and using 4/91(CHⅡ) type vaccines could improve the protection rate of laying hens against IBV.