| 摘要: |
| 【目的】分析2014-2021年陕西省猪群猪流行性腹泻病毒（PEDV）主要毒力基因的生物学信息特征，揭示陕西省PEDV流行毒株基因变异情况，为防控猪流行性腹泻提供理论参考。【方法】参考PEDV全基因序列设计4对引物，采用RT-PCR方法分段扩增10株陕西省PEDV流行毒株S基因。利用生物信息分析软件，将获得的PEDV流行毒株S基因与GenBank中公开的57株PEDV序列进行比对分析。【结果】获得了10株陕西省PEDV流行毒株S基因全序列，长度为4 149～4 167 bp。将序列上传GenBank，获得相应的登录号为OL855978～OL855987。系统进化树分析显示，67个PEDV毒株分为G1a、G1b、G2a和G2b 4个亚群，10株PEDV流行毒株均属于G2b亚群，且遗传距离较近，与我国多个省区近年流行毒株亲缘关系较近。同源性分析结果表明，10株流行毒株之间S基因核苷酸序列同源性为95.4%～98.3%，氨基酸同源性为91.0%～98.1%；10株流行毒株与疫苗毒株S基因核苷酸序列同源性为91.7%～98.5%，氨基酸同源性为87.8%～98.5%。与G1a亚群的SD-M、CV777疫苗毒株核苷酸、氨基酸相比同源性均较低，而与G2b亚群的AJ1102、LNCT2、LW/L、XJ-DB2疫苗毒株核苷酸、氨基酸相比同源性均较高。与CV777 S蛋白相比较，共有88个氨基酸位点出现变异，变异位点占总位点数的6.36%（88/1 383），其中在59～62位氨基酸有7株毒株出现了QGVN插入，在140位氨基酸有8株毒株出现N插入，在160～161位氨基酸有7株毒株出现DG缺失。S蛋白主要的中和表位、抗原表位和单抗识别表位出现多个变异位点。二级结构预测发现，与CV777相比较，多数流行毒株S蛋白的α螺旋、无规则卷曲占比稍有增加，β转角、延伸占比有所下降。S蛋白糖基化位点预测结果表明，与CV777株相比，流行毒株有多个引入或缺失的糖基化位点。【结论】陕西省PEDV流行毒株S蛋白抗原性发生了较大变化，推测疫苗免疫保护效果下降与此密切相关。 |
| 关键词: 猪流行性腹泻病毒 S基因 基因序列分析 生物学信息 陕西省 |
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| 基金项目:陕西省科技计划项目（2021NY-037）；咸阳职业技术学院重点科研项目（2021KJB01）；陕西省自然科学基金项目（2021JQ-900）；咸阳市科技计划项目（2020k02-63） |
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| Cloning and biological information analysis of S gene of porcine epidemic diarrhea virus in Shaanxi |
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ZHU Xiaofu,WU Xujin,ZHENG Hongqing,et al
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| Abstract: |
| 【Objective】This study analyzed biological information characteristics of main virulence genes of porcine epidemic diarrhea virus (PEDV) in pig herd in Shaanxi from 2014 to 2021 and revealed genetic variation of the PEDV epidemic strain in Shaanxi to provide references for preventing and controlling pig diarrhea.【Method】Referenced to the complete PEDV gene sequence,4 pairs of primers were designed and the S gene was amplified by RT PCR method.Using biological information analysis software,the obtained PEDV epidemic strain S gene was compared and analyzed with the 57 PEDV sequences published in GenBank.【Result】The full sequences of S gene of 10 PEDV epidemic strains in Shaanxi were obtained with length of 4 149-4 167 bp,and the sequences were uploaded to GenBank with accession numbers of OL855978-OL855987.Phylogenetic tree analysis showed that the 67 PEDV strains were divided into 4 subgroups of G1a,G1b,G2a and G2b.The 10 PEDV epidemic strains belonged to the G2b subgroup with close genetic distance and they were closely related to the virus strains circulating in many provinces of China in recent years.The homology analysis showed that the nucleotide sequence homology of the S gene among the 10 epidemic strains was 95.4%-98.3% and the amino acid homology was 91.0%-98.1%.The 10 epidemic strains had 91.7%-98.5% homology with the S gene,and the amino acid homology was 87.8%-98.5%.The strains had low homology with nucleotides and amino acids of SD-M and CV777 vaccine strains of the G1a subgroup and high homology with AJ1102,LNCT2,LW/L,and XJ-DB2 vaccine strains of the G2b subgroup.Compared with CV777 S protein,there were 88 amino acid sites with mutations,and the mutation sites accounted for 6.36% (88/1 383) of total sites.There were 7 strains with QGVN insertions from 59 to 62,and 8 strains with N insertions from 140.The 7 strains showed DG deletion from 160 to 161.The main neutralizing epitope,antigen epitope and monoclonal antibody recognition epitope of S protein had variant sites.The secondary structure prediction found that the proportions of alpha helix and random coils of S protein in most popular strains increased slightly,while the proportions of beta turn and extended strand decreased compared with CV777.The prediction of glycosylation sites of S protein showed that the epidemic strain had multiple introduced or deleted glycosylation sites compared with the CV777 strain.【Conclusion】The antigenicity of the S protein of PEDV epidemic strain in Shaanxi had major changes,and it was related to decline in immune protection of vaccines. |
| Key words: porcine epidemic diarrhea virus S gene gene sequence analysis biological information Shaanxi |
