猪场环境中苍蝇携带的PRRSV NSP2及ORF5基因遗传特征差异性分析

Differences in Genetic Diversity of PRRSV NSP2 and ORF5 Genes Harbored by Flies in Pig Farm Environment

为了解猪场环境中苍蝇携带的PRRSV的遗传特征,初步评估昆虫媒介传播PRRSV的潜在风险。从已证实感染PRRSV的猪场收集苍蝇和感染猪的淋巴结,分别提取RNA后采用RT-PCR扩增PRRSV的NSP2和ORF5基因,结合DNASTAR等生物学软件将其测序后的序列与其他PRRSV代表株的NSP2和ORF5基因进行生物信息学分析。结果表明:苍蝇源PRRSV NSP2基因与该猪场猪源及其他PRRSV代表株的NSP2基因核苷酸同源性为45.9%~95.9%,氨基酸同源性为33%~92.9%;ORF5基因核苷酸的同源性为61.5%~95.2%,氨基酸的同源性为32.5%~90.9%。进一步的序列分析结果显示苍蝇源与猪场猪源以及PRRSV代表株的NSP2和ORF5基因之间存在多个氨基酸位点的替换和缺失。进化树结果表明苍蝇源和该猪场猪源PRRSV的NSP2和ORF5基因均在同一分支,属于美洲型毒株,但二者分别与PRRSV GD株和NVDC株同源关系最近。综上表明,苍蝇源和该猪场猪源以及PRRSV代表株的NSP2和ORF5基因存在不同程度的差异,这些差异是否会影响PRRSV生物学特性需要后续进一步研究。研究结果对PRRSV传播途径的研究和初步评估公共卫生安全具有重要意义。

To learn the genetic characteristics of PRRS Vharboredby fliesin the environment and preliminary assessment to the potential transmissionrisks of PRRSV by insect vector.The NSP2 and ORF5 genes of PRRSV were amplified by RT-PCR after RNA was extracted from flies and the lymph nodes of pigs infected with PRRSV,respectively.The sequences of PRRSV NSP2 and ORF5 genes were compared with those of other representative strains by DNASTAR and other biological software.The results showed that the nucleotide identity of PRRSV NSP2 gene derived from flies was 45.9%-95.9%compared with those of pigs in farm and other PRRSV representative strains,the amino acid identity was 33%-92.9%,and the nucleotide identity of ORF5 gene was 61.5%-95.2%,the consistency of amino acids was 32.5%-90.9%.Besides,the results offurther sequence analysisshowed that there were multiple substitutions and deletions of amino acidbetween PRRSV NSP2 and ORF5 genes from flies,pigs in this farm and PRRSV representative strains.In addition,thephylogenetic tree results showed that the PRRSV NSP2 and ORF5 genes from flies and pigs in this pig farm were in the same branch and belonged to American type strain,but they had the closest homologous relationship with PRRSV GD strain and NVDC strain,respectively.In summary,the genes of PRRSV were different derived from flies,pigs and PRRSV represent strains.Whether these differences will affect the biological characteristics of PRRSV,whichrequires further research.The results of this study are of great significance for the study of PRRSV transmission pathways and public healthpreliminary evaluation.