河南鸡群马立克氏病病毒流行毒株的分子进化分析

Evolutionary Analysis of Field Marek's Disease Virus Prevalent in Chicken Flocks in Henan Province

为了解鸡马立克氏病病毒流行毒株的分子特征，对2012－2014年河南省发病鸡群的临床病料进行了采集，并对MDV 132 bp重复序列进行了PCR扩增，同时对meq、gE、gI基因进行了克隆和序列测定。结果表明，9份病料中均可扩增出与132 bp双拷贝大小相符的PCR主产物；meq、gE、gI基因的核苷酸序列同源性与国内外参考毒株相比，分别为98．5％～100％，98．8％～100％和98．0％～100％；基于这些基因构建的系统发生树的分析结果表明，与美国、澳大利亚、日本以及印度的MDV分离株相比，目前，河南省鸡群中流行的MDV与此前分离的河南流行株进化关系较近，并且与其他国内分离株共同形成一个较大的独立进化分支。

To investigate the molecular characteristics of Marek′s disease virus （ MDV ） prevalent in chicken flocks in Henan Province ,liver tissues were sampled from the suspecious cases in the flocks suffered from MD from 2012 to 2014.We amplified the MDV 132 bp repeat sequence from these tissues by polymerase chain reaction （PCR） and simultaneously,the meq,gE and gI genes were amplified,cloned,sequenced and then compared with the reference MDV strains and/or isolates.The main amplicons of the 132 bp repeat PCR products were the same size as 2 copies of the 132 bp repeats,similar to that of the positive control （GX0101）.The sequences of meq,gE and gI genes cloned from clinical tissues were relatively conserved , with the homology among 98 .5%-100%, 98.8%-100%and 98 .0%-100%respectively compared to the reference MDV isolates and/or strains .Based on the sequences of meq,gE and gI genes,the phylogenetic analysis were performed and the results showed that com-pared to the strains or isolates from USA ,Australia,Japan and India ,the MDVs prevalent recently in Henan Prov-ince were genetically closer to the previously reported Henan MDV isolates .Together with the isolates from the other regions in China ,the Chinese isolates formed an independent branch in the phylogenetic tree .This study provides more detailed information regarding the field MDVs circulating in Henan Province and may be meaningful for the further control of MD .