Identification and Comparative Analysis of Venom Proteins in a Pupal Ectoparasitoid, Pachycrepoideus vindemmiae

Abstract

Parasitoid wasps inject venom containing complex bioactive compounds to regulate the immune response and development of host arthropods and sometime paralyze host arthropods. Although extensive studies have been conducted on the identification of venom proteins in larval parasitoids, relatively few studies have examined the pupal parasitoids. In our current study, a combination of transcriptomic and proteomic methods was used to identify 64 putative venom proteins from Pachycrepoideus vindemmiae, an ectoparasitoid of Drosophila. Expression analysis revealed that 20 tested venom proteins have 419-fold higher mean expression in the venom apparatus than in other wasp tissues, indicating their specialization to venom. Comparisons of venom proteins from P. vindemmiae and other five species spanning three parasitoid families detected a core set of "ancient" orthologs in Pteromalidae. Thirty-five venom proteins of P. vindemmiae were assigned to the orthologous groups by reciprocal best matches with venoms of other pteromalids, while the remaining 29 were not. Of the 35 categories, twenty-seven have orthologous relationships with Nasonia vitripennis venom proteins and 25 with venoms of Pteromalus puparum. More distant relationships detected that five and two venom proteins of P. vindemmiae are orthologous with venoms of two Figitidae parasitoids and a Braconidae representative, respectively. Moreover, twenty-two venoms unique to P. vindemmiae were also detected, indicating considerable interspecific variation of venom proteins in parasitoids. Phylogenetic reconstruction based on a set of single-copy genes clustered P. vindemmiae with P. puparum, N. vitripennis, and other members of the family Pteromalidae. These findings provide strong evidence that P. vindemmiae venom proteins are well positioned for future functional and evolutionary studies.

The Venom of the Ectoparasitoid Wasp Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae) Induces Apoptosis of Drosophila melanogaster Hemocytes

“…Our recent study showed that the venom of P. vindemiae is a complex mixture of at least 64 proteins [28], some of which can potentially be cytotoxic and capable of inducing apoptosis. An example is calreticulin which is involved in cytotoxic processes [46] and also present in the venom of N. vitripennis [8,47] and P. puparum [48].…”

“…Our recent work has demonstrated that the venom of P. vindemiae is composed of a large number of proteins [28] responsible for manipulating the host physiology, including the immune system [2], although the mechanisms involved are largely unknown. In the present study, we monitored the dynamic changes in the number of plasmatocytes, lamellocytes and crystal cells after parasitism by P. vindemiae using D. melanogaster transgenic lines with hemocytes expressing a specific GFP (Green Fluorescent Protein) tag.…”

A venom protein, Kazal‐type serine protease inhibitor, of ectoparasitoid Pachycrepoideus vindemiae inhibits the hemolymph melanization of host Drosophila melanogaster

“…As mentioned in our previous study, the crude venom of P. vindemiae strongly inhibited the hemolymph melanization of host D. melanogaster (Yang et al, 2019), and an abundant component, PvKazal, was subsequently identified by combined transcriptomic and proteomic analyses (Yang et al, 2020). Further genomic‐level quest showed that P. vindemiae only encodes one Kazal gene.…”

“…Our previous study reported that P. vindemiae venom proteins strongly inhibited the hemolymph melanization of host Drosophila melanogaster (Yang et al, 2019), and SPIs are one of the most commonly abundant components in wasp venoms (Poirié, Colinet, & Gatti, 2014). Accordant with these fact, we identified a Kazal‐type serine proteinase inhibitor in venoms of P. vindemiae (PvKazal) by combining transcriptome and proteome analyses (Yang et al, 2020). However, little research has drawn on any systematic research into its roles in host melanization regulation.…”

“…The venom apparatus and carcass (minus the venom apparatus) of fully mated female wasps at 2–7 days posteclosion (PE) were separated according to the previous description (Yang et al, 2020). All samples were individually collected and total RNA was extracted as the manufacturer's instruction followed by a quantitative determination using NanoDrop 2000 (Thermo Fisher Scientific).…”