猪圆环病毒Ⅱ型的分离与全基因组序列分析

Isolation and genomic sequence analysis of porcine circovirus type 2 from pigs

从福建省表现为断奶猪多系统衰竭综合征的猪群中分离到两株猪圆环病毒Ⅱ型(PCV2),分别命名为FUQING0401和PUTIAN0401。通过对这两个分离株的全基因组序列测定,并同GenBank登录的12个代表毒株进行了遗传进化分析,结果表明：福建省两分离株的ORF1核苷酸同源率为97.5％,rep蛋白之间有6个氨基酸的差别,ORF2的核苷酸同源率为99.7％,而两者氨基酸同源率为98.7％。福建省两分离株与加拿大、美国、欧洲以及中国其他地方毒株之间的同源性很高,遗传进化分析表明这两毒株与其他代表毒株可分为几个小分支,但它们之间的核苷酸同源率在91.6％～99.9％,并没有发现福建的两个毒株之间存在地区特异性。

Post-weaning multisystemic wasting syndrome （PMWS） is an emerging disease m swme. rorcme clrcovirus type 2 （PCV2） has been associated with the PMWS. Two PCV2 strains were isolated from pigs showing signs of PMWS in Fujian Province. They were denominated FUQING0401 and PUTIAN0401. the sequencing of 2 PCV2 strains along with the phylogenetic analysis of these strains and those of 12 PCV2 sequences published in GenBank were compared. Sequence analysis of the complete genome indicated that the Fujian PCV2 strains were closely related to each other but also to other PCV2 strains originating from Canada, USA, Europe and China. Sequence analysis of ORF1 genes of the 2 strains revealed that the extent of nucleotide homologous was 97.5%. The amino acid sequences alignment of the PCV2 replicatase protein identified 6 amino acid heterogeneity. Capsid protein genes of PUTIAN0401 and FUQING0401 homologous rate was 99.7%, and the amino acid homologous rate was 98.7%. Phylogenetic analysis revealed that the 14 strains could be divided into several clusters, but the homologous rate was different from 91.6 % to 99.9%. The two strains from Fujian were spread in small groupings and an association with geographic origin could not be established.