A diverse gut virome in natural populations of Drosophila melanogaster

Drosophila melanogaster is not only one of the most important models of antiviral immunity in invertebrates, but is also a powerful model for research of the gut microbiome. Although recent studies have continued to improve our knowledge of the fly gut microbiota, the viral component of the microbiome has remained unexplored.

Here we explore the viral component of the Drosophila melanogaster gut microbiome using deep metagenomic DNA sequencing. We recovered 3040 non-redundant viral contigs, most of which were bacteriophage-associated sequences, resulting in 167 viral Metagenome-Assembled Genomes. Many of these sequences showed limited similarity to reference viruses and included bacteriophages related to tailed double-strand DNA phage lineages, with putative links to major gut-associated bacteria of D. melanogaster, including Lactobacillus, Acetobacter, and Gluconobacter. Our functional annotation and discovery of auxiliary metabolic genes suggested that these bacteriophages encode putative functional potential related to microbial metabolism and genetic information processing. We also identified evidence of known fly pathogens Drosophila Kallithea nudivirus, Vesanto bidna-like virus, and Drosophila Linvill Road densovirus, some of which were common in our studied populations.

Our findings reveal a complex and diverse phage community in the D. melanogaster gut microbiome, paving the way to study host-phage related research in the natural microbial communities.