Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan.
Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
J Virol. 2019 Jan 17;93(3). doi: 10.1128/JVI.01144-18. Print 2019 Feb 1.
White spot syndrome virus (WSSV) is a crustacean-infecting, double-stranded DNA virus and is the most serious viral pathogen in the global shrimp industry. WSSV is the sole recognized member of the family , and the lack of genomic data on other nimaviruses has obscured the evolutionary history of WSSV. Here, we investigated the evolutionary history of WSSV by characterizing WSSV relatives hidden in host genomic data. We surveyed 14 host crustacean genomes and identified five novel nimaviral genomes. Comparative genomic analysis of identified 28 "core genes" that are ubiquitously conserved in ; unexpected conservation of 13 uncharacterized proteins highlighted yet-unknown essential functions underlying the nimavirus replication cycle. The ancestral gene set contained five baculoviral infectivity factor homologs and a sulfhydryl oxidase homolog, suggesting a shared phylogenetic origin of and insect-associated double-stranded DNA viruses. Moreover, we show that novel gene acquisition and subsequent amplification reinforced the unique accessory gene repertoire of WSSV. Expansion of unique envelope protein and nonstructural virulence-associated genes may have been the key genomic event that made WSSV such a deadly pathogen. WSSV is the deadliest viral pathogen threatening global shrimp aquaculture. The evolutionary history of WSSV has remained a mystery, because few WSSV relatives, or nimaviruses, had been reported. Our aim was to trace the history of WSSV using the genomes of novel nimaviruses hidden in host genome data. We demonstrate that WSSV emerged from a diverse family of crustacean-infecting large DNA viruses. By comparing the genomes of WSSV and its relatives, we show that WSSV possesses an expanded set of unique host-virus interaction-related genes. This extensive gene gain may have been the key genomic event that made WSSV such a deadly pathogen. Moreover, conservation of insect-infecting virus protein homologs suggests a common phylogenetic origin of crustacean-infecting and other insect-infecting DNA viruses. Our work redefines the previously poorly characterized crustacean virus family and reveals the ancient genomic events that preordained the emergence of a devastating shrimp pathogen.
白斑综合征病毒（WSSV）是一种感染甲壳类动物的双链 DNA 病毒，是全球虾类养殖业中最严重的病毒性病原体。WSSV 是该科唯一公认的成员，而其他尼马病毒的基因组数据缺乏，掩盖了 WSSV 的进化历史。在这里，我们通过研究隐藏在宿主基因组数据中的 WSSV 亲属来探讨 WSSV 的进化历史。我们调查了 14 种宿主甲壳类动物的基因组，鉴定出了 5 种新的尼马病毒基因组。对鉴定出的 28 个“核心基因”进行比较基因组分析，这些基因在 中普遍保守；13 个未被描述的蛋白质的意外保守性突出了尼马病毒复制周期未知的基本功能。祖先基因集包含 5 个杆状病毒感染性因子同源物和一个硫氧还蛋白同源物，表明 和昆虫相关的双链 DNA 病毒具有共同的进化起源。此外，我们还表明，新基因的获得和随后的扩增加强了 WSSV 独特的辅助基因库。独特的包膜蛋白和非结构毒力相关基因的扩张可能是使 WSSV 成为致命病原体的关键基因组事件。WSSV 是威胁全球虾类养殖的最致命的病毒性病原体。WSSV 的进化历史一直是个谜，因为很少有 WSSV 的亲属，即尼马病毒被报道过。我们的目标是利用隐藏在宿主基因组数据中的新型尼马病毒的基因组来追溯 WSSV 的历史。我们证明，WSSV 是从一组多样化的感染甲壳类动物的大型 DNA 病毒中出现的。通过比较 WSSV 和其亲属的基因组，我们表明 WSSV 拥有一套扩展的独特的宿主-病毒相互作用相关基因。这种广泛的基因获得可能是使 WSSV 成为致命病原体的关键基因组事件。此外，昆虫感染病毒蛋白同源物的保守性表明，感染甲壳类动物的 和其他昆虫感染的 DNA 病毒具有共同的进化起源。我们的工作重新定义了以前描述不佳的甲壳类病毒家族，并揭示了预先注定虾类毁灭性病原体出现的古老基因组事件。
