基因组学与应用生物学

本研究于2009至2014年间在广西南宁、防城港和梧州三市活禽交易市场中分离获得12株H6亚型禽流感病毒(AIV)毒株。通过RT-PCR、序列测定及基因序列分析,结果表明,扩增获得的12株毒株基因大小均为1 701 bp,与Gen Bank中所登录的HA基因大小一致;其氨基酸序列推导结果发现12株分离毒株裂解位点氨基酸序列均为PQIETRG,只含有一个碱性氨基酸,符合低致病禽流感病毒的特点;对糖基化位点进行分析,结果发现HA基因中存在8个潜在糖基化位点,其中只有毒株GX2161的182~184 aa处发生了交替,其氨基酸序列为R-N-T,这与高致病力毒株的R-X-R/K-R的分子特征不同,推测GX6121毒株可能为典型的低致病力毒株。12个分离毒株与Gen Bank中公开登录的其它20个H6亚型AIV毒株的遗传进化树分析表明,防城港的4株毒株与越南株LC050583处于同一分支上,梧州的3株毒株与越南株LC042081处于同一分支,表现出较明显的地域性,而由于地理位置的影响,南宁的5株毒株则与越南株LC050583、广西株HQ599858、JX304770形成三个分支,表现出较近亲缘性,这表明AIV中HA存在一定的遗传变异性。本研究在分子水平上为有效防控广西活禽市场中H6亚型AIV的感染提供参考。

In this research, we got 12 strains of H6 subtype avian influenza virus(AIV) isolated from live poultry market in Nanning, Fangchenggang and Wuzhou of Guangxi started from 2009 to 2014. Based on the analysis of RT-PCR, sequencing and their sequence, the results showed that the length of all 12 strains were 1 701 bp, which were the same size of HA gene as those in the Gen Bank. The amino acid deduced found that all the amino acid of the cleavage site were PQIETRG, containing only one alkaline amino acid, which present the characteristics of low pathogenic AIV. The glycosylation sites analysis displayed that eight potential glycosylation sites were existed in the HA gene, but there was only one alternate in the GX2161(182~184 aa), and its amino acid sequence was R-N-T, which was different from the molecular characteristic of R-X-R/K-R in highly pathogenic strain,therefore, we speculated that GX6121 should be a typical low pathogenic avian influenza virus strain. The phylogenetic tree analysis of H6 subtype AIV in 12 isolates and 20 reference strains in Gen Bank demonstrated that 4 strains from Fangchenggang and a Vietnam strain LC050583 were in a same branch, and three Wuzhou strains were in the same branch with Vietnam strain LC042081, which expressed significant regionality. However,the five strains from Nanning shared closely relationship with Vietnam strain LC05583, Guangxi strain HQ599858 and JX304770, respectively because of the effect of the geographical location. All these results indicated that there were some genetic variations of HA genes in AIV. Our study would provide a reference for effectively control the infection of H6 Subtype AIV in Guangxi live poultry market.