PRRSV SC-GY变异株Nsp2、ORF5、ORF3基因遗传变异分析  

Genetic variation analysis of Nsp2,ORF5 and ORF3 of PRRSV SC-GY strain from Sichuan province

作　　者：陈希文[1,2] 李莲[2] 尹苗[1] 赖守勋 汪谦[2] 罗文涛[2] 叶兆美 王雄清[1] 周杰珑[2] 

机构地区：[1]绵阳师范学院动物应用技术研究所,四川绵阳621000 [2]西南林业大学生命科学学院,云南昆明650224 [3]四川铁骑力士集团冯光德实验室,四川绵阳621006

出　　处：《中国兽医学报》2017年第8期1433-1441,共9页Chinese Journal of Veterinary Science

基　　金：四川省科技厅和重点实验室资助项目(2013JY0127/ESP1505);四川省教育厅自然科学研究资助项目(16ZA0321)

摘　　要：为了监测PRRSV流行毒株的基因变异情况,采用RT-PCR方法对四川省广元市某疑似猪繁殖与呼吸综合征病毒(PRRSV)发病猪场病料进行分子鉴定,获得1株PRRSV命名为SC-GY株,并对SC-GY株的Nsp2、ORF5及ORF3基因进行测序比对和系统进化树构建。结果表明,SC-GY株为Nsp2基因发生30个氨基酸不连续缺失、ORF3基因第17位插入1个丝氨酸(S)的美洲型高致病性PRRSV变异毒株,其Nsp2、ORF5、ORF3基因与VR2332、SC2012、CH-1a、JXA1、HUN4、NADC30、HENAN-XINX等国内外代表毒株的核苷酸同源性分别为70.3%~97.9%,82.4%~97.6%,83.1%~98.2%,编码氨基酸同源性分别为62.3%~96.3%,78.0%~95.7%,81.6%~96.5%;而与LV等欧洲型毒株的核苷酸同源性分别为18.9%,60.8%,63.7%,编码氨基酸同源性分别为14.0%,54.9%,57.2%。基因遗传进化树分析表明,SC-GY株与JXA1、TJ、HUN4等前期分离的毒株以及近期在四川周边分离的SC2012、SCwhn09CD、SCwhn14DY等毒株都相距较远。由此表明,该地区PRRSV在当前高频度活疫苗免疫下,流行毒株基因仍在不断变异,猪场应减少PRRSV活疫苗的免疫并加强对临床PRRSV流行毒株的监测。To monitor genetic variation of porcine reproductive and respiratory syndrome virus （PRRSV） ,RT-PCR was used to identify a sample suspected of PRRSV infection. A PRRSV named SC-GY strain was obtained,and its Nsp2,0RF5 and ORF3 genes were used for sequence align- ment and phylogenetie tree construction. The results showed that SC-GY strain is highly patho- genic PRRSV American variant strains with Nsp2 gene discontinuous deletion of 30 amino acids, ORF3 gene aal7 a serine （S） insert. Comparing to VR2332, CH-1a, JXA1, HUN4, NADC30, HENAN-XINX and SC2012 ,the Nsp2,ORF5 and ORF3 of SC-GY shared 70.3%-97.9% ,82.4%- 97.6% and 83.1%-98.2% of nueleotide similarity,and 62.3%-96.3%,78.0%-95.7% and 81.6%- 96.5% of deduced amino acid similarity;and compared to LV they shared only 18.9% ,60.8% and 63.7% of nueleotide similarity,and 14.0% ,54.9% and 57.2% of deduced amino acid similarity. The phylogenetic tree revealed that the SC-GY formed independent small branches although it belonged to the same subgroup as highly pathogenic PRRSV strains. The results showed that in high frequency live vaccine immunization of currently PRRSV, the gene of PRRSV epidemic strain is still in constant variation. Vaccination of live PRRSV vaccines should be reduced and surveillance of PRRSV strains should be enhanced.

关 键 词：PRRSV NSP2 ORF5 ORF3 遗传变异 

分 类 号：S852.659.6[农业科学—基础兽医学]