Long-read genome sequencing and assembly ofLeptopilina boulardi: a specialistDrosophilaparasitoid

Abstract

<jats:title>ABSTRACT</jats:title><jats:p><jats:italic>Leptopilina boulardi</jats:italic> (Hymenoptera: Figitidae) is a specialist parasitoid of <jats:italic>Drosophila</jats:italic>. The <jats:italic>Drosophila</jats:italic>-<jats:italic>Leptopilina</jats:italic> system has emerged as a suitable model for understanding several aspects of host-parasitoid biology. However, a good quality genome of the wasp counterpart was lacking. Here, we report a whole-genome assembly of <jats:italic>L. boulardi</jats:italic> to bring it in the scope of the applied and fundamental research on <jats:italic>Drosophila</jats:italic> parasitoids with access to epigenomics and genome editing tools. The 375Mb draft genome has an N50 of 275Kb with 6315 scaffolds &gt;500bp and encompasses &gt;95% complete BUSCOs. Using a combination of <jats:italic>ab-initio</jats:italic> and RNA-Seq based methods, 25259 protein-coding genes were predicted and 90% (22729) of them could be annotated with at least one function. We demonstrate the quality of the assembled genome by recapitulating the phylogenetic relationship of <jats:italic>L. boulardi</jats:italic> with other Hymenopterans. The key developmental regulators like Hox genes and sex determination genes are well conserved in <jats:italic>L. boulardi</jats:italic>, and so is the basic toolkit for epigenetic regulation. The search for epigenetic regulators has also revealed that <jats:italic>L. boulardi</jats:italic> genome possesses DNMT1 (maintenance DNA methyltransferase), DNMT2 (tRNA methyltransferase) but lacks the <jats:italic>de novo</jats:italic> DNA methyltransferase (DNMT3). Also, the heterochromatin protein 1 family appears to have expanded as compared to other hymenopterans. The draft genome of <jats:italic>L. boulardi</jats:italic> (Lb17) will expedite the research on <jats:italic>Drosophila</jats:italic> parasitoids. This genome resource and early indication of epigenetic aspects in its specialization make it an interesting system to address a variety of questions on host-parasitoid biology.</jats:p>