Unmapped RNA Virus Diversity in Termites and their Symbionts.

Callum Le Lay,Mang Shi,Nathan Lo,Aleš Buček,Edward Holmes,Thomas Bourguignon

doi:10.3390/v12101145

Abstract

Despite their ecological importance, nothing is known about the diversity and abundance of RNA viruses in termites (Termitoidae). We used a metatranscriptomics approach to determine the RNA virome structure of 50 diverse species of termite that differ in both phylogenetic position and colony composition. From these samples, we identified 67 novel RNA viruses, characterized their genomes, quantified their abundance and inferred their evolutionary history. These viruses were found within or similar to those from the Togaviridae, Iflaviridae, Polycipiviridae, Flaviviridae, Leviviridae, Narnaviridae, Mitoviridae, Lispivirdae, Phasmaviridae, Picobirnaviridae and Partitiviridae. However, all viruses identified were novel and divergent, exhibiting only 20% to 45% amino acid identity to previously identified viruses. Our analysis suggested that 17 of the viruses identified were termite-infecting, with the remainder likely associated with the termite microbiome or diet. Unclassified sobemo-like and bunya-like viruses dominated termite viromes, while most of the phylogenetic diversity was provided by the picobirna- and mitovirus-like viruses. Of note was the identification of a novel flavi-like virus most closely related to those found in marine vertebrates and invertebrates. Notably, the sampling procedure had the strongest association with virome composition, with greater RNA virome diversity in libraries prepared from whole termite bodies than those that only sampled heads.

Highlights

Invertebrates, insects, are the most diverse lineage of animals [1]
We identified seven novel viruses (Moksystermes virus, Hiksystermes virus, Jaksystermes virus, Nuksystermes virus, Laksystermes virus and Feksystermes virus) that fall within the Picorna–Calici group, these viruses occupied a range of phylogenetic positions and included some of the most divergent ones found in this study (Figures 1 and 8)
We present the first survey of the RNA virome of termites, demonstrating that these important organisms harbor a diverse array of RNA viruses

Summary

Introduction

Invertebrates, insects, are the most diverse lineage of animals [1] This diversity is likely to be paralleled by the diversity of their viromes, rendering invertebrates a potentially rich resource of novel viruses. Are invertebrate RNA viruses diverse, but the viromes of individual species are often complex with levels of abundance that are often far higher than those seen in vertebrate species [3,4]. Despite this metagenomic revolution, the current sample of the virosphere remains fragmentary, leading to substantial gaps in our understanding of RNA virus diversity, evolution and ecology. A simple first step in changing this picture is to characterize more of those RNA viruses present

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Conclusion