两株高致病性PRRSV湖北分离株ORF5与Nsp2基因序列分析

Sequence Analysis for ORF5 Gene and Nsp2 Gene of Two Hubei PRRSV Strains

关键词:  猪繁殖与呼吸综合征病毒  ORF5基因  Nsp2基因  序列分析

Key words:  porcine reproductive and respiration syndrome virus  ORF5 gene  Nsp2 gene  sequence analysis

摘要:

2013年从湖北两个发病猪场采集疑似猪繁殖与呼吸综合征病料，接种Marc-145 细胞，可致明显细胞病变，各分离到1株猪繁殖与呼吸综合征病毒(HBHS株和HBXN株)。采用 RT-PCR 方法，对ORF5基因序列和Nsp2基因部分序列进行扩增并测序，并用DNA MAN软件将测序结果与国内外发表的13株参考毒株进行比对分析。结果显示，2株分离株Nsp2基因与国内高致病性JXA1、GD2007、GD2008毒株的氨基酸同源性很高，介于98.5%～99.5%；且该基因与国内其他变异株有完全一致的缺失特征；ORF5基因与国内高致病性毒株的氨基酸同源性为98.1%~ 99.5%，且系统进化树遗传距离很近，同处一个基因群中，而与CH-1a等经典毒株较远。这两株分离株均属于PRRSV美洲型变异株，此结论为该病的防治及疫苗的设计奠定了基础。

Abstract:

Samples were collected from two farms in Hubei province with suspected clinical signs of porcine reproductive and respiratory syndrome in 2013, two porcine reproductive and respiratory syndrome virus isolates (HBHS and HBXN) were isolated in Marc-145 cells. The ORF5 and partial Nsp2 genes of the isolates were amplified using RT- PCR which was followed sequencing. Multiple sequences of ORF5 and Nsp2 amino acids were compared with those of 13 reported PRRSV strains and analyzed using DNA MAN software. The results showed that homology between Nsp2 gene of two PRRSV isolates and highly pathogenic JXA1, GD2007, GD2008 strains was 98.5%～99.5% in amino acids sequence, and the same time this gene had the same deletion compared with other variation strains in China; As to ORF5 gene, the homology was 98.1% ~ 99.5%, in amino acids sequence with highly pathogenic PRRSV strains, and phylogenetic tree was very close with these strains, but phylogenetic tree was far away with CH-1a classic strain. The data indicated that the two PRRSV isolates might be the mutant isolates of PRRSV American genotype. And our study will lay a theoretical basis for the disease prevention and vaccine design.