2017—2019年猪流行性腹泻病毒广西流行毒株遗传多样性分析

为掌握广西猪流行性腹泻病毒(PEDV)流行毒株的遗传变异情况,本研究对2017-2019年从广西各地采集的腹泻样品,应用RT-PCR方法进行检测,并随机选取部分PEDV阳性样品进行S、M、N基因的扩增、测序和分析。结果显示,共获得PEDV S基因序列23株、M基因和N基因序列各25株。同源性分析显示,广西流行毒株间核苷酸和氨基酸序列同源性在S基因为90.6%~100%和89.6%~100%,在M基因为97.0%~100%和96.9%~100%,在N基因为95.9%~100%和95.9%~100%。序列比对显示,广西流行毒株S1基因的氨基酸序列存在缺失、突变和插入现象,且各毒株之间存在差异。基于S、M、N基因绘制遗传进化树,获得相似的拓扑结构图,广西流行毒株主要分布在S基因的GⅠb、GⅡa亚群,M基因的GⅡa、GⅡb亚群,N基因的GⅢ亚群。遗传进化速率测算显示,广西流行毒株及国内外参考毒株S、M、N基因的平均进化速率分别为7.39×10-4、1.43×10-4和2.96×10-4substitutions/site/year,S基因的变异速度最快。表明PEDV广西流行毒株存在遗传多样性,应加强病原监测和流行病学调查,为有效防控PED提供基础数据。

Genetic diversity of porcine epidemic diarrhea virus in Guangxi Province from 2017 to 2019

To understand the genetic variation of porcine epidemic diarrhea virus(PEDV)strains in Guangxi Province,clinical diarrhea samples collected from Guangxi Province during 2017 to 2019 were detected by RT-PCR.S,M and N genes were amplified from partial PEDV positive samples selected randomly,sequenced and analyzed.As a result,23 S gene sequences,25 M gene sequences and 25 N gene sequences of PEDV were acquired.Homology analysis revealed that the nucleotide and amino acid homology of S,M and N genes were 90.6%—100%and 89.6%—100%,97.0%—100%and 96.9%—100%,95.9%—100%and95.9%—100%,respectively.Sequence alignment analysis showed that the amino acid sequences of S1 gene existed deletion,mutation and insertion,and there existed genetic variation among PEDV strains from Guangxi Province.The phylogenetic trees based on S,M and N genes showed similar topology diagrams.The PEDV strains from Guangxi Province mainly distributed in GⅠb and GⅡa subgroups of S gene,GⅡa and GⅡb subgroups of M gene,and GⅢsubgroup of N gene.Evolutionary rate analysis showed that the evolutionary rates of S,M,and N genes of Guangxi strains and other reference strains were7.39×10-4,1.43×10-4 and 2.96×10-4 substitution/site/year,respectively,showing that S gene had the fastest evolution among three genes.The results indicated that there existed genetic diversity of PEDV strains from Guangxi Province and it should be reinforced for pathogen survailence and epidemiological investigation to provide basic data for effective prevention and control of PED.