Institute of Plant Science and Resources (IPSR), Okayama University, Chuou 2-20-1, Kurashiki, Okayama 710-0046, Japan.
Virus Res. 2018 Jan 15;244:75-83. doi: 10.1016/j.virusres.2017.11.006. Epub 2017 Nov 6.
Recent studies illustrate that fungi as virus hosts provides a unique platform for hunting viruses and exploring virus/virus and virus/host interactions. Such studies have revealed a number of as-yet-unreported viruses and virus/virus interactions. Among them is a unique intimate relationship between a (+)ssRNA virus, yado-kari virus (YkV1) and an unrelated dsRNA virus, yado-nushi virus (YnV1). YkV1 dsRNA, a replicated form of YkV1, and RNA-dependent RNA polymerase, are trans-encapsidated by the capsid protein of YnV1. While YnV1 can complete its replication cycle, YkV1 relies on YnV1 for its viability. We previously proposed a model in which YkV1 diverts YnV1 capsids as the replication sites. YkV1 is neither satellite virus nor satellite RNA, because YkV1 appears to encode functional RdRp and enhances YnV1 accumulation. This represents a unique mutualistic virus/virus interplay and similar relations in other virus/host fungus systems are detectable. We propose to establish the family Yadokariviridae that accommodates YkV1 and recently discovered viruses phylogenetically related to YkV1. This article overviews what is known and unknown about the YkV1/YnV1 interactions. Also discussed are the YnV1 Phytoreo_S7 and YkV1 2A-like domains that may have been captured via horizontal transfer during the course of evolution and are conserved across extant diverse RNA viruses. Lastly, evolutionary scenarios are envisioned for YkV1 and YnV1.
最近的研究表明，真菌作为病毒宿主为寻找病毒以及探索病毒/病毒和病毒/宿主相互作用提供了一个独特的平台。这些研究揭示了许多尚未报道的病毒和病毒/病毒相互作用。其中，一种(+)ssRNA 病毒 yado-kari 病毒(YkV1)和一种不相关的 dsRNA 病毒 yado-nushi 病毒(YnV1)之间存在一种独特的密切关系。YkV1 的 dsRNA 是 YkV1 的复制形式，以及 RNA 依赖性 RNA 聚合酶，都被 YnV1 的衣壳蛋白包裹。虽然 YnV1 可以完成其复制周期，但 YkV1 依赖 YnV1 才能存活。我们之前提出了一个模型，即 YkV1 将 YnV1 衣壳蛋白作为复制位点转移。YkV1 既不是卫星病毒也不是卫星 RNA，因为 YkV1 似乎编码了功能性 RdRp 并增强了 YnV1 的积累。这代表了一种独特的互利病毒/病毒相互作用，并且在其他病毒/宿主真菌系统中可以检测到类似的关系。我们建议建立 Yadokariviridae 科，以容纳 YkV1 和最近发现的与 YkV1 具有系统发育关系的病毒。本文概述了关于 YkV1/YnV1 相互作用的已知和未知信息。还讨论了 YnV1 Phytoreo_S7 和 YkV1 2A 样结构域，它们可能是在进化过程中通过水平转移捕获的，并在现存的各种 RNA 病毒中保守。最后，对 YkV1 和 YnV1 进行了进化情景设想。
