摘要:
采用RT-PCR方法及动物回归试验,对PRRSV-FJ09A毒株的ORF5与NSP2基因组进行遗传变异分析和致病性研究。结果表明:(1)与PRRSV-VR2332标准毒株比较,ORF5基因片段的核苷酸及推导的氨基酸的同源性分别为87.6%和88.1%,PRRSV-FJ09A毒株存在多个氨基酸发生突变,主要集中在抗原表位、毒力相关位点和糖基化位点;NSP2基因片段的核苷酸及推导的氨基酸的同源性分别为80.9%和77.0%,PRRSV-FJ09A毒株分3处共缺失31个氨基酸。(2)与国内2006年后流行的变异型PRRSV毒株比较, PRRSV-FJ09A毒株ORF5基因片段的核苷酸及推导的氨基酸的同源性分别为98.5%~99.7%和97.5%~99.5%, NSP2基因片段的核苷酸及推导的氨基酸的同源性分别为98.4%~99.3%和97.3%~98.9%,PRRSV-FJ09A毒株在NSP2基因片段多一处缺1个苯丙氨酸(F)。结论:PRRSV-FJ09A毒株为美洲型毒株,与国内流行的变异型PRRSV-FJ06A毒株的亲缘关系比较近。该毒株对30日龄的仔猪具有高致病性。
Abstract:
To fully understand the knowledge of variant porcine reproductive and respiratory syndrome virus (PRRSV) genetic variation and pathogenicity, the ORF5 and NSP2 genomes of PRRSV-FJ09A strain were amplified by RT-PCR and sequenced. Comparing with PRRSV-VR2332, ORF5 gene shared 87.6%of nucleotide homologies and 88.1% of the deduced amino acid homologies, there were point mutations within deduced amino acids, focus on amino acids of associated with virulence, epitope and N-glycosylation sites;NSP2 gene shared 80.9% of nucleotide homologies and 77.0% of the deduced amino acid homologies, and it shared a common feature of 31 amino acids deletion in three places which one place more of a phenylalanine(F) than other local reports. Comparing these sequences with Chinese PRRSV strains published after 2006,ORF5 gene shared 98.5%-99.7% of nucleotide homologies and 97.5%-99.5% of the deduced amino acid homologies, NSP2 gene shared 98.4%-99.3% of nucleotide homologies and 97.3%-98.9% of the deduced amino acid homologies. The phylogeneic tree revealed PRRSV-FJ09A strain isolated had closer relationship with PRRSV-FJ06A strain. According to the animal experiment PRRSV-FJ09A had a high pathogenicity to 30 d pigs.
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