杂交野猪猪繁殖与呼吸综合征病毒分离及其ORF6、ORF7基因的序列分析

试验旨在研究杂交野猪猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus, PRRSV) 辽宁分离株的遗传变异情况及分子生物学特征.用Marc-145细胞从辽宁某杂交野猪场疑似猪繁殖与呼吸综合征(porcine reproductive and respiratory syndrome, PRRS)病猪血液中分离到1株病毒,该分离毒株经Marc-145细胞6次传代后出现稳定的细胞病变,采用RT-PCR方法对分离病毒进行ORF6和ORF7基因的扩增、克隆和测序,并与已知序列毒株的相应片段进行同源性比对.结果表明,分离毒株的ORF6、ORF7基因与国内外美洲型毒株的核苷酸同源性分别为96.0%～100.0%、94.5%～99.4%;氨基酸同源性分别为89.6%～100.0%、87.3%～98.7%;与欧洲型代表毒株LV的ORF6、ORF7基因差异较大,核苷酸同源性分别为70.4%、70.1%,氨基酸同源性分别为48.8%、49.7%.推测辽宁杂交野猪体内分离毒株在基因型上属于美洲型毒株.

Sequence Analysis of ORF6 and ORF7 Genes of PRRSV Isolated from Hybrid Wild Boars

The research aimed to study genetic variation and molecular biological characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) from Liaoning hybrid wild boars. A virus strain was isolated by Marc-145 cells from blood of Liaoning hybrid wild boars with suspected porcine reproductive and respiratory syndrome (PRRS) infection. The isolation could induce regular cytopathogenic effects (CPE) on Marc-145 cells after six passages.ORF6 and ORF7 genes of PRRSV isolates were amplified by RT-PCR. The products were sequenced after cloning into pMD18-T vectors respectively. The sequences were analyzed and compared with other PRRSV isolates in GenBank.The results showed that ORF6 and ORF7 genes of the virus isolated shared 96.0% to 100.0%, 94.5% to 99.4%, sequence identities with that of American type strains at home and abroad, at nucleotide level and 89.6% to 100.0%, 87.3% to 98.7% respectively at the amino acid level. However, only 70.4% and 70.1% nucleotide, 48.8% and 49.7% amino acid homologies were found between ORF6, ORF7 genes and Europe type representative strains LV. It indicated that this isolate strain from Liaoning hybrid wild boars belongs to American type PRRSV.