广州市活禽市场7株H9N2亚型禽流感病毒全基因进化分析

摘要

为了解广州市活禽交易市场H9N2亚型禽流感病毒(AIV)的变异特点和流行情况,本研究对2015年5月～2016年6月分离的7株H9N2亚型AIV进行全基因组的遗传进化分析.结果显示,7株H9N2亚型AIV均属于G57基因型,其中有4株分离株的部分内部基因与人源H7N9亚型病毒株基因的核苷酸同源性在99％以上.HA裂解位点未发现碱性氨基酸的替换,HA潜在糖基化位点存在添加或缺失现象,HA蛋白aa155位和aa226位分别为苏氨酸(T)和亮氨酸(L),具有结合人流感病毒受体能力.NA蛋白颈部存在氨基酸缺失,M1蛋白N30D、T139A、T215A,NS1蛋白P42S等突变可能会增加病毒的致病性.结果表明广州市活禽交易市场H9N2亚型AIV的基因型趋于稳定,但其糖基化位点和受体结合位点等呈现多样化,并且H9N2亚型AIV的内部基因能够为其它亚型AIV提供内部片段,其对养殖行业及人类健康产生潜在威胁,仍需对其进行持续的监测.%To investigate the variation characteristics and epidemic trend of H9N2 avian influenza virus (AIV) in live poultry markets in Guangzhou,7 H9N2 AIV isolates were isolated for the phylogenetic analysis from May 2015 to June 2016.The results showed that all 7 isolates belonged to G57 genotype.Partial internal genes of 4 isolates shared more than 99％ nucleotide identities with human origin H7N9 virus.There was no substitution of continuous alkaline amino acids in cleavage sites in HA gene,and the potential glycosylation sites of HA had insertions or deletions.The 155th and 226th amino acids of HA protein were threonine (T) and leucine(L),which were reported to contribute to the human-type receptor binding of H9N2 virus.The 3-amino-acid deletion of 63 to 65 in the NA stalk,N30D,T139A,T215A in M1 and p42S in NS1 protein could enhanced the virulence of the viruses in this survey.In conclusion,the genotypes of H9N2 AIV in Guangzhou live poultry markets were stable,but the potential glycosylation sites and receptor binding sites were diversified,and the H9N2-origin intemal gene segments could reassort with other subtypes of AIVs,which posed a great threat to the breeding industry and human health,and it suggests that continuous surveillance of H9N2 is necessary.