猪圆环病毒2型吉林分离株的全基因组序列分析

Complete genomic sequence analysis of porcine circovirus type 2 from Jilin

采用PCR扩增1株吉林新分离的PCV2-2017全基因组序列,经过测序拼接后进行了序列分析。毒株PCV2-2017基因全长1 767 bp,在GenBank上进行同源性比对,同源性在96%～99%之间;与法国株AF055394同源性可达99%,与美国株AF055391、四川株HM102350同源性最低,为96%。PCV2中ORF1编码Rep蛋白,核苷酸和氨基酸同源性达到99%,ORF1突变很小,相对保守;ORF2基因全长为702 bp,编码Cap蛋白,氨基酸同源性达94%～99%,核苷酸同源性与美国株比对,可达96%,与法国株和国内部分毒株同源性达99%,是变异主要发生部位,共有12处点突变;ORF3编码蛋白,核苷酸同源性高达100%,说明变异不大。基因的遗传进化分析表明,PCV2-2017吉林新分离株全基因组与法国株AF055394亲缘关系最近,同属于PCV-2b亚型;与AY322001、AB426905和国内GU370064、AY691169、AY969004、DQ180393毒株亲缘关系较远。

The complete genome sequence of a newly isolated Jilin PCV2 -2017 was amplified by PCR. Sequence analysis was carried out after sequencing and splicing. The gene size of PCV2 -2017 strain was 1767bp,and the homology of the nucleotide was from 96 % to 99% when compared with those in GenBank. The nucleotide homology was 99% with France AF055394 and the United States strain AF055391. The homology with 96% Sichuan strain HM102350 was 96%. For ORF1 encoding Rep protein of PCV2, its nucleotide homology reached 99%. The results showed that the PCV2 mutation in ORF1 was very small and relatively conservative. The length of the ORF2 geneis 702bp, which encoded the Cap protein. The homology of amino acid was 94%-99% and nucleotide homology reached from 96% to 99% ORF2 was a variable region. For ORF3 the nucleotide homology was 100%, indicating that there is little variation. Phylogenetic analysis showed that complete genome of the strain PCV2-2017,isolated from Jilin was the closest with the France strain AF055394 and it belonged to PCV - 2b subtype. It had the farest relationship with AY322001, Japan AB426905, Zhejiang AY691169 Xinjiang GU370064, Henan AY969004, and Fujian DQ180393 strains.