Gong Wenjie, Zhang Li, Lu Zongji, Jia Junjie, Wang Meng, Peng Zhicheng, Guo Huancheng, Shi Jishu, Tu Changchun
Institute of Military Veterinary Medicine, Academy of Military Medical Sciences, Changchun, China.
Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
Arch Virol. 2016 Sep;161(9):2613-7. doi: 10.1007/s00705-016-2932-6. Epub 2016 Jun 18.
Current subgenotype 2.1 isolates of classical swine fever virus (CSFV) play a dominant role in CSF outbreaks in China, and a novel sub-subgenotype 2.1g of CSFV was recently identified, but the complete genome sequence of this new sub-subgenotype has not been reported. In this study, complete genome of 2.1g isolate GD19/2011 collected from Guangdong province of China in 2011 was sequenced. It was found to be 12,298 nucleotides (nt) in length, including a 375-nt 5'UTR, a 11,697-nt opening reading frame (ORF), and a 227-nt 3'UTR. GD19/2011 shared 91.0-93.7 % and 95.6-97.5 % nt and amino acid sequence identity, respectively, with other subgenotype 2.1 isolates. The topology of a phylogenetic tree constructed based on complete genome sequences of GD19/2011 and other CSFV isolates was identical to that obtained with full-length E2 gene sequences, but it was significantly different from those obtained with the 5'UTR and core sequences. Serial passages of GD9/2011 in PK-15 cells generated a highly cell-adapted virus stock with an infectious titer of 10(7.8) TCID50/ml at the 12(th) passage in which two amino acid substitutions, S476R and N2494S, were observed in comparison with the complete polyprotein sequence of the original isolate from kidney tissue, GD19/2011. This is the first report of the complete genome sequence of a 2.1g isolate, and the GD19/2011 isolate will be useful for further analysis of the evolution and virulence of CSFV isolates.
目前，经典猪瘟病毒（CSFV）的2.1亚基因型毒株在中国猪瘟疫情中占据主导地位，并且最近鉴定出一种新的CSFV 2.1g亚亚基因型，但该新亚亚基因型的完整基因组序列尚未见报道。本研究对2011年从中国广东省采集的2.1g毒株GD19/2011进行了全基因组测序。结果发现其长度为12,298个核苷酸（nt），包括一个375 nt的5'非翻译区（UTR）、一个11,697 nt的开放阅读框（ORF）和一个227 nt的3'UTR。GD19/2011与其他2.1亚基因型毒株的核苷酸和氨基酸序列同一性分别为91.0 - 93.7%和95.6 - 97.5%。基于GD19/2011和其他CSFV毒株的全基因组序列构建的系统发育树拓扑结构与基于全长E2基因序列获得的拓扑结构相同，但与基于5'UTR和核心序列获得的拓扑结构显著不同。GD9/2011在PK - 15细胞中连续传代，在第12代时产生了一种高度适应细胞的病毒株，其感染滴度为10(7.8) TCID50/ml，与原始肾脏组织分离株GD19/2011的完整多聚蛋白序列相比，观察到两个氨基酸替换，即S476R和N2494S。这是2.1g分离株完整基因组序列的首次报道，GD19/2011分离株将有助于进一步分析CSFV分离株的进化和毒力。
