Whole Genome Sequence of the Parasitoid Wasp Microplitis demolitor That Harbors an Endogenous Virus Mutualist

• Main Authors: Gaelen R. Burke, Kimberly K. O. Walden, James B. Whitfield, Hugh M. Robertson, Michael R. Strand
• Format: Article
• Language: English
• Published: Oxford University Press 2018-09-01
• Series: G3: Genes, Genomes, Genetics
• Subjects: symbiosis; Hymenoptera; Braconidae; Microplitis demolitor bracovirus (MdBV); Polydnaviridae
• Online Access: http://g3journal.org/lookup/doi/10.1534/g3.118.200308

Microplitis demolitor (Hymenoptera: Braconidae) is a parasitoid used as a biological control agent to control larval-stage Lepidoptera and serves as a model for studying the function and evolution of symbiotic viruses in the genus Bracovirus. Here we present the M. demolitor genome (assembly version 2.0), with a genome size of 241 Mb, and a N50 scaffold and contig size of 1.1 Mb and 14 Kb, respectively. Using RNA-Seq data and manual annotation of genes of viral origin, we produced a high-quality gene set that includes 18,586 eukaryotic and 171 virus-derived protein-coding genes. Bracoviruses are dsDNA viruses with unusual genome architecture, in which the viral genome is integrated into the wasp genome and is comprised of two distinct components: proviral segments that are amplified, circularized, and packaged into virions for export into the wasp’s host via oviposition; and replication genes. This genome assembly revealed that at least two scaffolds contain both nudivirus-like genes and proviral segments, demonstrating that at least some of these components are near each other in the genome on a single chromosome. The updated assembly and annotation are available in several publicly accessible databases; including the National Center for Biotechnology Information and the Ag Data Commons. In addition, all raw sequence data available for M. demolitor have been consolidated and are available for visualization at the i5k Workspace. This whole genome assembly and annotation represents the only genome-scale, annotated assembly from the lineage of parasitoid wasps that has associations with bracoviruses (the ‘microgastroid complex’), providing important baseline knowledge about the architecture of co-opted virus symbiont genomes.