2011-2014年河南省鸡群马立克氏病病毒流行株的分子进化及基因重组分析

发布时间：2018-09-18 18:49

【摘要】：马立克氏病病毒(Marek’s disease virus,MDV)是少数感染自然宿主后,可诱发淋巴瘤的禽疱疹病毒之一,其感染引起的鸡马立克氏病(Marek’s disease,MD)也是最早可以用抗病毒疫苗来预防肿瘤发生的疾病。为了解鸡MDV流行毒株的分子特征,本研究对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和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132bp双拷贝大小相符的PCR主产物;meq、gE和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。除了MDV,禽网状内皮增生症病毒(Reticuloendotheliosis virus,REV)也是导致家禽免疫抑制性疾病和肿瘤病最重要的病原之一。由于MDV和REV具有相似的组织嗜性,常混合感染于同一鸡群,因此这两种病毒的共感染对家禽养殖业危害巨大。此前研究表明,MDV基因组中可人工或自然重组REV的部分基因组片段,如长末端重复序列(long terminal repeat,LTR),这种重组对MDV的病原学特性可能具有重要影响。为了解国内鸡群MDV和REV的共感染和自然重组状况,本研究对分离自河南商品蛋鸡群的17个MDV分离株进行了分析,结果发现其中HNGS206和HNXZ103的病毒基因组中存在REV-LTR的重组插入。进一步的研究表明这两个毒株不是MDV与REV自然重组的流行毒株,其基因组中LTR的插入可能发生于临床病例鸡共感染后的病毒分离培养过程中。本研究的结果提示河南鸡群中MDV和REV的共感染较为普遍,但MDV与REV自然重组毒株的流行状况仍需要进一步的流行病学监测。
[Abstract]:Marek's disease virus (Marek's disease virus,MDV) is one of the few avian herpes virus that can induce lymphoma after it is infected with natural host. The chicken Marek's disease (Marek's disease,MD) caused by Marek's disease is also the first disease that can be prevented by antiviral vaccine. In order to understand the molecular characteristics of chicken MDV epidemic strains, the clinical samples of chickens infected in Henan Province from 2012 to 2014 were collected, the repeat sequence of MDV 132 bp was amplified by PCR, and the genes of meq,gE and gI were cloned and sequenced. The results showed that the nucleotide sequence homology of the major PCR products, mequger E and gI, which were identical to the 132bp double copy size, could be amplified from 9 samples of the disease, compared with the reference strains at home and abroad. The analysis of the phylogenetic tree based on these genes showed that compared with the MDV isolates from the United States, Australia, Japan and India, At present, the MDV prevalent in Henan chicken herd is closely related to the evolution of previously isolated Henan strains and forms a large independent evolutionary branch with other domestic isolates. In addition to MDV, avian reticuloendotheliosis virus (Reticuloendotheliosis virus,REV), it is also one of the most important pathogens leading to immunosuppressive diseases and tumor diseases in poultry. Because MDV and REV have similar tissue preference, they are often mixed infected in the same chicken herd, so the co-infection of these two viruses is harmful to poultry industry. Previous studies have shown that part of the genome of REV that can be recombined artificially or naturally, such as long terminal repeat sequence (long terminal repeat,LTR), may have an important effect on the etiological characteristics of MDV. In order to understand the co-infection and natural recombination of MDV and REV in domestic chickens, 17 MDV isolates isolated from Henan commercial laying hens were analyzed. The results showed that the recombinant insertion of REV-LTR was found in the viral genomes of HNGS206 and HNXZ103. Further studies showed that these two strains were not the natural recombination of MDV and REV, and the insertion of LTR in the genome of the two strains might occur during the isolation and culture of the virus after co-infection in clinical chicken. The results of this study suggest that co-infection of MDV and REV is common in Henan chickens, but the prevalence of natural recombinant strains of MDV and REV is still in need of further epidemiological monitoring.
【学位授予单位】：河南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S852.65

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