猪圆环病毒2型XJ-SW株全基因组的克隆与序列分析

Cloning and sequence analysis of the complete genome of porcine circovirus type 2 Xinjiang Shawan strains

应用PCR方法对采集自新疆沙湾地区某猪场的疑似仔猪多系统衰竭综合征病料猪圆环病毒2型(PCV2)全基因组进行了扩增,确定了2份病料中的PCV2的分子特征,命名为XJ-SW1、XJ-SW2(Gen-Bank登录号:JN639856,JN639857)。经对阳性样品进行克隆、测定,并应用软件进行全基因组核苷酸序列比对分析。结果显示,2株病毒的基因组全长均为1 768nt;XJ-SW1株与我国山东DE株(GenBank登录号:HM142897)的同源性最高(为97.91%);XJ-SW2株与韩国G2284株(GenBank登录号:JF317587)的同源性最高(为97.51%)。PCV2全基因组序列的进化分析表明,2株病毒为PCV2e基因亚型;对2株病毒与5个不同基因亚型的15株病毒的ORF2氨基酸序列进行比较,结果显示,XJ-SW1、XJ-SW2在ORF2的氨基端与PCV2d同源性较高,在羧基端与PCV2e同源性较高。表明,在新疆沙湾猪场流行的PCV2毒株为PCV2e,该毒株的ORF2存在一定变异。

The complete genomic sequences of 2 strains of porcine circovirus type 2（PCV2）,named XJ-SW1 and XJ-SW2,were amplified by using polymerase chain reaction（PCR） from clinically suspected postweaning multisystemic wasting syndrome（PMWS） samples,which were collected in Shawan of Xinjiang.The genome sequences were submitted to the GenBank（with accession of No.JN639856 and JN639857）.Complete genome sequences of the two strains were aligned with those available in the GenBank.Results showed that the full length of genomic sequence of PCV2 XJ-SW1 and XJ-SW2 strain were both 1 768 nt and the XJ-SW1 strain shared the highest identity（97.91.%） with that of China DE strain（GenBank accession No.HM142897）,while the XJ-SW2 strain shared the highest identity（97.51%） with the South Korea G2284 strain（GenBank accession No.JF317587）.Phylogenetic analyses demonstrated that the two isolates were classified into PCV2e genotype.The ORF2-encoded amino acid sequence comparison of the two PCV2 strains XJ-SW1 and XJ-SW2,and 5 different genotypes of 15 PCV2 strains showed that XJ-SW1 and XJ-SW2 shared higher homology with PCV2d in the N-terminal and higher homology with PCV2e in the C-terminal.In conclusion,the PCV2e group strains were predominant prevailing strain in Shawan of Xinjiang.There was a certain variation between the ORF2s of the two strains.