Analysis of the RNA virome of basal hexapods.

Sabina Ott Rutar,Dusan Kordis

doi:10.7717/peerj.8336

Abstract

The diversity and evolution of RNA viruses has been well studied in arthropods and especially in insects. However, the diversity of RNA viruses in the basal hexapods has not been analysed yet. To better understand their diversity, evolutionary histories and genome organizations, we searched for RNA viruses in transcriptome and genome databases of basal hexapods. We discovered 40 novel RNA viruses, some of which are also present as endogenous viral elements derived from RNA viruses. Here, we demonstrated that basal hexapods host 14 RNA viral clades that have been recently identified in invertebrates. The following RNA viral clades are associated with basal hexapods: Reo, Partiti-Picobirna, Toti-Chryso, Mono-Chu, Bunya-Arena, Orthomyxo, Qinvirus, Picorna-Calici, Hepe-Virga, Narna-Levi, Tombus-Noda, Luteo-Sobemo, Permutotetra and Flavi. We have found representatives of the nine RNA viral clades that are present as endogenous genomic copies in the genomes of Machilis (Monocondylia) and Catajapyx (Diplura). Our study provided a first insight into the diversity of RNA viruses in basal hexapods and demonstrated that the basal hexapods possess quite high diversity of RNA viral clades.

Highlights

The analysis of the invertebrate RNA virosphere uncovered a vast diversity of RNA viruses in insects, their evolutionary histories, highly diverse and dynamic genome organizations, as well as the presence of distinct RNA viromes in diverse insect lineages (Shi et al, 2016)
The collection of the NCBI Transcriptome Shotgun Assembly (TSA) and Whole Genome Sequence (WGS) databases for basal hexapods offers an attractive possibility to obtain the first insight into the diversity of their RNA viromes
Phylogenies of basal hexapod RNA viruses (Figs. 1–3) demonstrated that they belong to numerous RNA viral clades

Summary

Introduction

The analysis of the invertebrate RNA virosphere uncovered a vast diversity of RNA viruses in insects, their evolutionary histories, highly diverse and dynamic genome organizations, as well as the presence of distinct RNA viromes in diverse insect lineages (Shi et al, 2016). Defined virus families, orders, floating genera and novel virus groups were merged together into 24 RNA viral clades. Their names reflect the presence of representative viral families or orders within each RNA viral clade (Shi et al, 2016; Shi et al, 2018). As demonstrated in phylogenetic analyses (Shi et al, 2016; Li et al, 2015), novel data connected plant and animal RNA viral clades, offering a possible interpretation for their dissemination through horizontal transfer by insect vectors (Shi et al, 2016; Li et al, 2015; Dolja & Koonin, 2018; Blanc & Gutierrez, 2015). Insects are a rich source of the RNA viral diversity because of their high taxa diversity, omnipresence and ecological interactions with vertebrates and plants

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