猪源牛病毒性腹泻病毒SH-28分离株的全基因组序列及遗传进化分析

Complete genomic sequencing and analysis of the pig bovine viral diarrhea virus strain SH-28

为了解猪源牛病毒性腹泻病毒(BVDV)与牛源BVDV在遗传特性上的差异,本试验对实验室分离保存的1株猪源BVDV(SH-28)进行了全基因组测序。利用反转录-聚合酶链式反应(RT-PCR)方法分段扩增了SH-28分离株的18条cDNA片段,分别克隆于pGEM-T质粒载体并进行测序,用CLUSTX(1.8)和Lasergene软件进行序列的剪切和拼接,最终获得SH-28基因组序列全长为12 279个核苷酸(nt),开放阅读框(ORF)长11 685nt,编码3 895个氨基酸(aa),5′-UTR和3′-UTR分别长385nt和206nt。全基因组进化树结果表明,虽然SH-28与HLJ-10同处于一个分支上,但其与XJ-04的全基因组核苷酸同源性最高(92.3%),而与另外2株猪源BVDV-1(ZM-95、SD0806)的亲缘性较远(70.0%、70.1%)。5′-UTR进化树结果显示,SH-28分离株属于BVDV-2a2基因亚型,而HLJ-10和XJ-04株属于BVDV-2a1。由此,我们推测SH-28很有可能是由牛源BVDV-2进化而来的,但不同于已发表的BVDV-2分离株。

The complete genorne of a pig bovine viral diarrhea virus （BVDV） SH-28 was sequenced in or- der to analyze the genetic difference between pig BVDV and bovine BVDV. Amplified by RT-PCR, 18 fragments of SH-28 were cloned into pGEM-T and then sent for sequencing by commerical serves. The retrieved sequences were timed and aligned with CI.USTX（1.8） and Lasergene. Ultimately, we obtained the complete sequence of SH-28. The genome of SH-28 comprises 12 279 nucleotides and contains a large open reading frame （ORF） encoding a polyprotein of 3 895 amino acids. The 5＇, 3＇-untranslated region （Sr-UTR, 3＇-UTR） are 385 nt and 206 nt, respectively. The phylogenetic tree of complete sequence showed that SH-28 and HI.J-10 were in the same branch,yet it was most similar to XJ-04 （92.3%） and divergent with the other pig BVIDV- 1 （ZM-95, SI）0806） （70.0%, 70. 1 %）. The phylogenetie tree of 5＇- UTR showed that SH-28 belonged to BVDV-2a2 while HI J-10 and XJ-04 were classified into BVDV- 2al. Therefore, we speculate that SH-28 is a new BVDV-2 isolate different from the previous BVDV-2 strains and may originate from bovine BVDV-2.