Genome of the Blueberry Stem Gall Wasp

Abstract

The blueberry stem gall wasp, Hemadas nubilipennis, is a parasitic wasp species that lays its eggs within the shoots of blueberry plants, inducing the formation of galls. These galls provide larvae with nourishment and protect them from environmental threats, as well as reducing the crop yields of affected blueberry bushes. Blueberries are a major agricultural product in Michigan, so parasitism by blueberry stem gall wasps could have a significant economic impact on the region. The assembly of the H. nubilipennis genome may help to develop better pest management strategies. In this project we performed sequencing, size estimation and assembly of the blueberry stem gall wasp genome. First, the DNA of a single organism was extracted and sequenced using Illumina paired-end technology. Then, the data was used to estimate genome size using k-mer counting. Finally, the genome was assembled de novo using the SPAdes assembler. The genome size of H. nubilipennis was found to be approximately 1Gb, similar to other plant gall forming parasitic wasps, but larger than other closely related non-plant gall forming parasitic wasps. The trend of significantly larger genome size associated with the plant gall forming trait was observed in many other Hymenopteran parasitic wasps. Structural and functional annotation of the assembled reference genome produced in this study will allow for the identification of genes associated with the plant gall forming trait. Additionally, identification of cytochrome p450 genes may be a starting point for the study of insecticide resistance in the species.