猪细环病毒k2型福建株ORF2基因克隆

为丰富福建省猪细环病毒的分子流行病学数据,本研究根据猪细环病毒1a型、1b型和k2型特异性检测引物对临床顽固性腹泻仔猪病料组织进行PCR检测,结果从1例病料中检测到猪细环病毒k2型阳性。并通过设计猪细环病毒k2型ORF2基因特异性引物对阳性病料扩增后进行克隆测序,获得猪细环病毒k2型ORF2基因完整编码区序列。分析发现所克隆的猪细环病毒k2型福建株ORF2基因全长为203 bp,编码有67个氨基酸。本实验株ORF2基因和猪细环病毒k2型代表株德国家猪分离株2p株(Gen Bank登录号AY823991)核苷酸同源性高达97.5%;和猪细环病毒1a型(Sd_TTV31株)和1b型(1p株)代表株核苷酸同源性均低于50.0%,分别为43.9%和47.3%。从遗传进化关系上看,本实验株ORF2基因和Gen Bank中猪细环病毒k2型处于同一遗传进化分支,而猪细环病毒1a型和猪细环病毒1b型均处于其他遗传分支。本研究首次在福建猪群中检测到猪细环病毒k2型感染。

Clone of the ORF2 Gene of Porcine Torque teno sus virus k2 in Fujian

To supplement molecular epidemiology data of porcine Torque teno sus virus in Fujian Province, specific primers targeting the porcine Torque teno sus virus genotype 1a, 1b and k2 were used to test the samples from piglets with refractory diarrhea syndrome. One sample was tested to be positive with porcine Torque teno sus virus k2, then the ORF2 gene fragments were cloned and sequenced. The results showed that the ORF2 gene of the porcine Torque teno sus virus k2 isolated in Fujian was 203 bp in length, coding 67 amino acids. Comparing with other porcine Torque teno sus virus strains, the cloned ORF2 gene sequence of Fujian isolate in this study shared 97.5% homologous sequence with the porcine Torque teno sus virus k2 isolate 2p strain; and shared 43.9% and 47.3% homologous sequence with porcine Torque teno sus virus 1a (Sd_TTV31 strain) and 1b (1p strain), respectively. According to the phylogenetic tree based on the ORF2 gene, the results demonstrated that the porcine Torque teno sus virus k2 isolated in Fujian shared the same branch with porcine Torque teno sus virus k2, while porcine Torque teno sus virus 1a and porcine Torque teno sus virus 1b strains occupied individual phylogenetic branch. All the results showed that the porcine Torque teno sus virus k2 was spreading in Fujian Province.