A56 Visualization of recombination in deformed wing virus infecting bees

Abstract

Honey bees suffer increasing colony mortality worldwide, partially caused by the spread of viral pathogens. Among these pathogens, deformed wing virus (DWV) is one of the major, widespread viruses of honey bees resulting in wing deformities and weakening colonies. DWV can be found in honey bees, bumble bees, and other wild bees as three major genotypes named DWV-A, -B (also named Varroa destructor virus 1), and -C. Various recombinants of DWV-A and -B have been previously found in honey bees, some of which have been suggested to have higher virulence over non-recombinant, parental virus. In most of these cases, recombinants were only shown as consensus sequences from previous assemblies and alignments and may not reflect the biological reality of all variants present within a host bee. It is therefore important to build a method of recombinant detection and quantification within mixed infections in single-host individuals, including both parental and various recombinant genomes, so as to evaluate the relevance of recombinants for viral genome evolution and the impact on hosts. Here, we propose to visualize and quantify these recombinants using next-generation sequencing data to better understand how these genomes evolve within bees. Our method will be performed directly from raw sequence reads from various datasets (including field and lab experiments as well as screening of public databases) in order to obtain an overview of DWV recombination in various in vivo and in vitro conditions. Recombination of viral genomes is a key point for virus evolution. The detection and quantification of recombination will facilitate analysis of the determinants of recombination and help in understanding the routes by which new viral variants emerge. The emergence of new (more virulent) recombinant viruses can result from acquisition of new capabilities, such as escape from host immunity or increased transmission rates. Recombination can also lead to adaptation to new environments and new hosts by a change in cell tropism, allowing cross-species transmission, which may be particularly relevant for bumble bees and wild bees infected by honey bee-derived DWV.