猪血清中PCV-2全基因组的克隆与序列分析

Clone and analysis of PCV-2 complete genome sequence in porcine serum

为研究从猪血清中分离的猪圆环病毒2型（Porcine circovirus type 2,PCV-2）与从发病猪组织中分离的PCV-2之间的差异、了解贵州地区PCV-2遗传变异情况、丰富贵州PCV-2全基因组序列库,试验采用来自贵州省毕节市金沙县、遵义市绥阳县、毕节市黔西县和贵阳市修文县的PCV-2抗体阳性猪血清,通过PCR扩增及通过T克隆获得了4株PCV-2全基因,分别命名为GZ-JS2015、GZSY2016、GZ-QX2014和GZ-XW2014,并进行测序;将测序结果与笔者收集的38株PCV-2的核苷酸序列进行比对分析。结果表明：在病毒血症期间猪血清中分离的PCV-2与从发病猪组织中分离的PCV-2并无太大差异;笔者收集的血清中贵州省为10株,其中8株为PCV-2b型、2株为PCV-2a型,说明在贵州地区流行的主要是PCV-2b型;来自贵州省同一地区的2株PCV-2处于不同的进化树分支上,与省外的PCV-2分离株亲缘关系较近,提示在贵州省流行的部分PCV-2可能由引种时流入。

The aim of the present study was to identify the difference between PCV-2 that isolated from porcine serum and diseased tissues,understand the genetic variation of Porcine circovirus type 2（ PCV-2） and enrich the sequence database of PCV-2 complete genome in Guizhou.In this experiment,four PCV-2 complete genomes were obtained by PCR amplification and T cloning from porcine serum that was positive by PCV-2 antibody detection in Guizhou province’s Bijie Jinsha county,Zunyi Suiyang county,Bijie Qianxi county and Guiyang Xiuwen county.The genomes were named GZ-JS2015,GZ-SY2016,GZ-QX2014 and GZ-XW2014,respectively. The genomes were sequenced and compared with the collected nucleotide sequences of 38 PCV-2. The results showed that there were no significant difference between PCV-2 isolated from serum during viremia and from diseased porcine tissues. GZ-SY2015 strain belongs to PCV-2 b type. Among 10 PCV-2 strains,8 strains belonged to PCV-2 b type. The results indicated that the PCV-2 b was a mainly epidemic disease in Guizhou area. Two PCV-2 strains from the same area of Guizhou were found on different branches of the phylogenetic tree. They were closed to the PCV-2 isolated from other province,respectively. The results suggested that part PCV-2 prevalent in Guizhou area might be flowed in when introduced fine pigs from other province.