2018年云南省思茅地区猪场蚊PCV2检测及ORF2基因遗传进化分析

Detection of PCV2 and genetic and evolutionary analysis of ORF2 gene in mosquitoes in Simao area of Yunnan Province in 2018

目的了解云南省思茅地区猪场蚊携带猪圆环病毒2型(PCV2)情况及蚊源PCV2的遗传进化特征。 方法采集云南省思茅地区3个猪场周围蚊标本94份并检测PCV2携带情况,PCR扩增ORF2基因,对得到的ORF2基因进行同源性、系统进化树分析和抗原位点比对分析。 结果PCR检测蚊PCV2阳性率为15.96%(15/94),得到的14个ORF2序列之间的核苷酸同源性为89.5%~99.9%,对应氨基酸同源性为86.2%~99.6%;与NCBI GenBank收录的22个参考ORF2序列的核苷酸同源性为79.9%~99.9%,对应的氨基酸同源性为79.5%~99.6%。系统进化树分析PCV2a亚型1个,PCV2b亚型5个,PCV2d亚型8个。抗原位点比对分析显示,PCV2Cap蛋白氨基酸变异位点主要位于50-70aa,131-140aa,200-220aa 3个区段。 结论云南省猪场蚊PCV2携带率较高,主要毒株为PCV2b和PCV2d亚型,且以PCV2d亚型较多,与我国当前猪感染PCV病毒型群体内流行情况相符。

Objective To investigate the mosquito carrying PCV2in pig farms in Simao area,Yunnan Province,and to determine the genetic and evolutionary characteristics of mosquito PCV2. Methods 94mosquito samples were collected from three pig farms in Simao,Yunnan Province,and PCV2was detected.The ORF2gene was amplified by PCR.Homology, phylogenetic tree analysis and antigenic site comparison analysis were performed on the ORF2gene. Results The positive rate of PCV2was 15.96%(15/94),the nucleotide homology between 14ORF2sequences was 89.5%-99. 9%,and the homology of corresponding amino acids was 86.2%-99.6%.The nucleotide homology of 14ORF2sequences obtained in this study and 22reference ORF2sequences published on Genbank was 79.9%-99.9%,and the homology of corresponding amino acids was 79.5%-99.6%.Phylogenetic tree analysis showed that there was 1PCV2a subtype,5PCV2bsubtypes and 8PCV2dsubtypes.The results of antigen site comparison showed that the amino acid variation sites of PCV2Cap protein obtained in this study were mainly located in three sections:50-70aa,131-140aa and 200-220aa. Conclusion The PCV2carrying rate of mosquitoes in yunnan province is high,the main strains are PCV2band PCV2dsubtypes,and the PCV2dis the most prevailing,which is consistent with the current prevalence of pig in China.