de novo Transcriptome Assembly of the Parasitoid Wasp Fopius arisanus Using RNA-Seq

Fopius arisanus is an egg-pupal parasitoid of Tephritid fruit flies. Its importance as biological control agent for these extremely invasive and damaging pest stems in F. arisanus ability to infect the flies during early developmental stages, and on its host range. In Hawaii, it was estimated that F. arisanus constitute up to 9% of the parasitoid guild, and the level of parasitism of the pest fruit fly species Bactrocera dorsalis (oriental fruit fly) can range between 65% and 70%, significantly reducing the infestation of fruits by the flies. However, for some other fly species Bactrocera cucurbitae (Melon fruit fly), F. arisanus was reported to have rather low parasitism rates. It is also known that this parasitoid wasp is able to discriminate hosts depending on the fruit substrate they are on. Knowledge on the genomic and transcriptomic of this species would help understanding the underlying mechanisms that contribute to parasitism behavior, for the design of better biological control strategies, and for the development of monitoring tools for parasitism rate in the field. We have sequenced and assembled the transcriptome of this wasp using tissue from four different life stages: larvae, pupae, adult males and adult females with the aim of contribute to the understanding of the biology and behavior of this important parasitoid. The de novo assembly was generated using the Trinity pipeline (Broad Institute) which yielded tens of thousands of transcripts, many being short, having low read support and/or no apparent open reading frame. To quality filter the assembly and generate a dataset that likely represents high quality, well supported transcripts, we used expression values, isoform composition, and ORF prediction to reduce the transcriptome assembly to a dataset that is similar in composition to model species in the family Hymenoptera.  To simplify this process, we developed Transvestigator, a software tool for filtering, annotating, and correcting de novo transcriptome assembles, and generating data files for NCBI submission.