马赛病毒上海分离株的分离和全基因组分析

Isolation and Genome Anlysis of Marseillevirus Shanghai Isolate

马赛病毒是一种感染棘阿米巴的大型双链DNA病毒,在世界各地都有这类病毒的分离报道。本研究从上海地区环境土壤样品中分离了一株马赛病毒。该病毒可以高效地感染棘阿米巴,病毒颗粒呈典型的二十面体结构,直径大约在0.25μm,基因组为368kb。病毒基因组DNA序列分析结果表明,该病毒属马赛病毒科的A系马赛病毒,与欧洲、澳大利亚等地报道的病毒株相似度极高。通过与分离自全球不同地区的另外四株马赛病毒比较发现大部分病毒基因都处于负选择,说明马赛病毒的核心基因非常保守并且足以支持病毒在不同地区的适应性。

Marseillevirus is an Acanthamoeba-infecting large dsDNA virus identified all over the world.Here we reported the isolation and identification of a new isolate of Marseillevirus,Marseillevirus shanghai isolate(Mar-SH2016)from soil sample in Shanghai,China.The virions have an icosahedral structure with diameter around 0.25μm.Complete genome sequencing showed that its genome size is 368 kb.Phylogeny analysis showed that it belongs to Marseillevirus lineage A.The selection pressures,represented by the ratio of the amount of nonsynonymous and synonymous mutations,were analyzed between Mar-SH2016 and four other isolates of lineage A Marseillevirus from Europe,Japan and Australia.Despite the long geographic distance bewteen the sites of isolation,most of the predicted viral genes are under negative selection.The results indicate that Marseillevirus core genes are highly conserved and sufficient to support virus adapted in different geographic area.