广东省猪生殖与呼吸综合征病毒主要结构蛋白基因的变异分析

Genetic variation analysis of major structural protein genes of PRRSV in swine from Guangdong Province

根据GenBank中猪生殖与呼吸综合征病毒(PRRSV)美洲株(ATCC VR-2332)基因序列分别设计合成了针对PRRSV ORF3、ORF5和ORF6基因的引物,利用RT-PCR从广东省送检的5份病料中均分别扩增得到了大小约787、630和550 bp的片段,将扩增的cDNA片段克隆入pMD 18-T载体并测序.应用DNAStar软件分析,并与国内外已发表毒株和疫苗株(RespPRRS/Repro、RespPRRS MLV)、LV4.2.1株的序列进行比较.结果显示,这5个毒株与CH-1a、HB-1(sh)、BJ-4、ATCC VR-2332、疫苗株等毒株ORF3、ORF5、ORF6的核苷酸同源性分别为87.2%～98.7%、85.4%～96.8%、91.8%～98.9%,推导的氨基酸同源性分别为84.6%～97.6%、84.5%～95.5%、94.8%～98.9%;而与LV4.2.1株的核苷酸同源性分别为56.1%～58.3%、54.4%～57.0%、62.2%～64.4%,推导的氨基酸同源性分别为53.9%～56.7%、54.0%～57.0%、78.0%～80.3%.基因系统发育树表明,广东省流行的PRRSV与HB-1(sh)株的亲缘关系比较近.

ORF3,ORF5 and ORF6 genes of 5 PRRSV Guangdong(GD) strains were obtained by RT-PCR and sequenced after being cloned directly into the pMD18-T. The sequences of ORF3,ORF5,ORF6 genes of the 5 GD isolates were compared with sequences of other PRRSV strains in GenBank by Blast and DNAStar software. The results showed that the ORF3, ORF5 and ORF6 of the 5 GD strains shared (87.2%)-98.7%,85.4%-96.8% and 91.8%-98.9% of nucleotide homology, and 84.6%-97.6%,(84.5%)-95.5% and 94.8%-98.9% of amino acid identity, with that of CH-1a, HB-1(sh), BJ-4, ATCC VR-2332, SP and the vaccine strain(RespPRRS/Repro, RespPRRS MLV), respectively. The ORF3, ORF5 and ORF6 of the 5 GD strains shared only 56.1%-58.3%, 54.4%-(57.0%) and 62.2%-64.4% of nucleotide homology, and (53.9%)-56.7%, 54.0%-57.0% and 70.2%-80.3% of amino acid homology with that of LV4.2.1, respectively. The phylogenetic trees revealed the 5 GD strains had close relationship with HB-1(sh).