A Novel RNA Virus in the Parasitoid Wasp Lysiphlebus fabarum: Genomic Structure, Prevalence, and Transmission.

Martina N Lüthi,Christoph Vorburger,Alice B Dennis

doi:10.3390/v12010059

Martina N Lüthi, Christoph Vorburger + Show 1 more

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https://doi.org/10.3390/v12010059

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Abstract

We report on a novel RNA virus infecting the wasp Lysiphlebus fabarum, a parasitoid of aphids. This virus, tentatively named “Lysiphlebus fabarum virus” (LysV), was discovered in transcriptome sequences of wasps from an experimental evolution study in which the parasitoids were allowed to adapt to aphid hosts (Aphis fabae) with or without resistance-conferring endosymbionts. Based on phylogenetic analyses of the viral RNA-dependent RNA polymerase (RdRp), LysV belongs to the Iflaviridae family in the order of the Picornavirales, with the closest known relatives all being parasitoid wasp-infecting viruses. We developed an endpoint PCR and a more sensitive qPCR assay to screen for LysV in field samples and laboratory lines. These screens verified the occurrence of LysV in wild parasitoids and identified the likely wild-source population for lab infections in Western Switzerland. Three viral haplotypes could be distinguished in wild populations, of which two were found in the laboratory. Both vertical and horizontal transmission of LysV were demonstrated experimentally, and repeated sampling of laboratory populations suggests that the virus can form persistent infections without obvious symptoms in infected wasps.

Highlights

The rise of next-generation sequencing technologies has enabled de novo sequencing of wild and non-model organisms, which has greatly facilitated virus discovery [1]
We report on a novel RNA virus infecting the wasp Lysiphlebus fabarum, a parasitoid of aphids
Based on phylogenetic analyses of the viral RNA-dependent RNA polymerase (RdRp), Lysiphlebus fabarum virus (LysV) belongs to the Iflaviridae family in the order of the Picornavirales, with the closest known relatives all being parasitoid wasp-infecting viruses

Summary

Introduction

The rise of next-generation sequencing technologies has enabled de novo sequencing of wild and non-model organisms, which has greatly facilitated virus discovery [1]. With this has come a mounting number of studies reporting novel viruses infecting all taxa, including insects [2,3,4,5,6]. A large number of species employ a parasitoid lifestyle, with up to 20% of all insects belonging to the parasitoid wasps [15,16]. As adults these species live freely, but their offspring develop on or inside a host and usually kill the host during the course of their development [17,18]

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