Laboratory Animal Center, Southwest Medical University, Luzhou, China.
School of Basic Medical Sciences, Zunyi Medical University, Zunyi, China.
Transbound Emerg Dis. 2021 Jul;68(4):2161-2170. doi: 10.1111/tbed.13864. Epub 2020 Nov 4.
Ranaviruses can infect both captive and wild cold-blooded vertebrates, leading to significant economic and environmental losses. With the cases of ranavirus infection increasing, many ranavirus genomic sequences were published, but little is known about ranavirus taxonomy on a whole-genome level. In this study, 44 ranaviruses core genes were identified in 32 ranaviruses genome sequences by using PanX. The neighbour-joining phylogenetic trees (NJ-tree) based on 44 ranaviruses core genes and 24 iridoviridae core genes and composition vector phylogenetic tree (CV-Tree) based on whole genome were constructed. The three of phylogenetic trees showed that 32 ranavirus isolates can be divided into 4 different subgroups including SGIV-like, EHNV-like, FV3-like and CMTV-like, and subgroups taxonomic position of three phylogenetic trees were consistent. However, the phylogenetic position of ToRV could not be determined if it belongs to FV3-like or CMTV-like group. Subsequently, we carried out dot plot analysis and confirmed that ToRV should belong to CMTV-like group. Based on dot plot analysis and phylogenetic trees, the taxonomic classification of ranaviruses was confirmed. Finally, four genes which are suitable for the construction of phylogenetic tree were selected from ranavirus core genes by recombination analysis, substitution saturation analysis and single-gene phylogenetic analysis. Phylogenetic tree based on concatenated sequences of the four selected genes showed that the classification of subgroups was identical with three of the phylogenetic trees. Conclusion: Our results confirmed taxonomic identification of ranaviruses; the four selected genes used in phylogenetic analysis will make taxonomic identification more convenient and accurate.
蛙病毒可感染人工养殖和野生冷血脊椎动物,导致重大的经济和环境损失。随着蛙病毒感染病例的增加,许多蛙病毒基因组序列被发表,但在全基因组水平上对蛙病毒的分类知之甚少。本研究通过 PanX 在 32 个蛙病毒基因组序列中鉴定了 44 个蛙病毒核心基因。基于 44 个蛙病毒核心基因和 24 个虹彩病毒科核心基因的邻接法系统发育树(NJ 树)和基于全基因组的组成向量系统发育树(CV 树)被构建。这三种系统发育树表明,32 个蛙病毒分离株可分为 4 个不同的亚群,包括 SGIV 样、EHNV 样、FV3 样和 CMTV 样,且三种系统发育树的亚群分类位置一致。然而,如果 ToRV 属于 FV3 样或 CMTV 样群,其系统发育位置则无法确定。随后,我们进行了点图分析并证实 ToRV 应属于 CMTV 样群。基于点图分析和系统发育树,对蛙病毒的分类进行了确认。最后,通过重组分析、替换饱和分析和单基因系统发育分析,从蛙病毒核心基因中选择了 4 个适合构建系统发育树的基因。基于这 4 个选定基因的串联序列构建的系统发育树显示,亚群的分类与三种系统发育树一致。结论:我们的结果证实了蛙病毒的分类鉴定;用于系统发育分析的 4 个选定基因将使分类鉴定更加方便和准确。