Proteo-transcriptomic insights into the venom composition of the ectoparasitoid Eupelmus urozonus

Ectoparasitoid venoms are 'cocktails' of bioactive molecules injected during oviposition to paralyze the host and remodel its physiology and immunity, but for many species of agro-ecological interest, the composition remains poorly defined. In this study, we aimed to describe the venom repertoire of Eupelmus urozonus in an integrated manner by combining transcriptomics of the venom glands and proteomics of the venom.

The assembly and annotation of the transcriptome, based on BLAST and Gene Ontology, revealed a strong representation of functions related to ion binding and biosynthetic processes, with top hits indicating a marked homology with Nasonia vitripennis. In parallel, LC-MS/MS analysis of venom proteins (from SDS-PAGE bands digested in-gel and queried against a database constructed from the transcriptome, with peptide ion score >18 and a minimum of four such peptides per protein) confidently identified 316 venom proteins; 75 of these have a predicted signal peptide and are therefore classified as predicted secretory components. The main functional classes include hydrolases, proteases, and related inhibitors, as well as stress- and transport-associated proteins. Overall, the venom includes putative immunomodulatory and metabolic factors with lineage-specific innovations, and a significant proportion of proteins are unannotated or potentially species-specific.

These results provide a solid basis for the functional validation of new candidate effectors and suggest that the venom of E. urozonus represents a reservoir of bioactive molecules with potential biotechnological applications, particularly in the context of sustainable pest management strategies. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.