title: Venom gland extract is not required for successful parasitism in the polydnavirus-associated endoparasitoid Hyposoter didymator (Hym. Ichneumonidae) despite the presence of numerous novel and conserved venom proteins.
abstract: The venom gland is a conserved organ in Hymenoptera that shows adaptations associated with life-style diversification. Few studies have investigated venom components and function in the highly diverse parasitic wasps and all suggest that the venom regulates host physiology. We explored the venom of the endoparasitoid Hyposoter didymator (Campopleginae), a species with an associated polydnavirus produced in the ovarian tissue. We investigated the effects of the H. didymator venom on two physiological traits of the host Spodoptera frugiperda (Noctuidae): encapsulation response and growth rate. We found that H. didymator venom had no significant effect on host cellular immunity or development, suggesting that it does not contribute to parasitism success. The host physiology seemed to be modified essentially by the ovarian fluid containing the symbiotic polydnaviruses. Proteomic analyses indicated that the H. didymator venom gland produces a large variety of proteins, consistent with the classical hymenopteran venom protein signature, including: reprolysin-like, dipeptidyl peptidase IV, hyaluronidase, arginine kinase or allergen proteins. The venom extracts also contained novel proteins, encoded by venom genes conserved in Campopleginae ichneumonids, and proteins with similarities to active molecules identified in other parasitoid species, such as calreticulin, reprolysin, superoxide dismutase and serpin. However, some of these proteins appear to be produced only in small amounts or to not be secreted. Possibly, in Campopleginae carrying polydnaviruses, the host-modifying activities of venom became redundant following the acquisition of polydnaviruses by the lineage.
authors.affiliation: INRA (UMR 1333), Université de Montpellier 2, "Insect-Microorganisms Diversity, Genomes and Interactions", Place Eugène Bataillon, CC101, 34095 Montpellier Cedex, France.
authors.forename: Tristan
authors.initials: T
authors.lastname: Dorémus
authors.forename: Serge
authors.initials: S
authors.lastname: Urbach
authors.forename: Véronique
authors.initials: V
authors.lastname: Jouan
authors.forename: François
authors.initials: F
authors.lastname: Cousserans
authors.forename: Marc
authors.initials: M
authors.lastname: Ravallec
authors.forename: Edith
authors.initials: E
authors.lastname: Demettre
authors.forename: Eric
authors.initials: E
authors.lastname: Wajnberg
authors.forename: Julie
authors.initials: J
authors.lastname: Poulain
authors.forename: Carole
authors.initials: C
authors.lastname: Azéma-Dossat
authors.forename: Isabelle
authors.initials: I
authors.lastname: Darboux
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Escoubas
authors.forename: Dominique
authors.initials: D
authors.lastname: Colinet
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gatti
authors.forename: Marylène
authors.initials: M
authors.lastname: Poirié
authors.forename: Anne-Nathalie
authors.initials: AN
authors.lastname: Volkoff
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005088:Exocrine Glands / Q000648:ultrastructure; D005260:Female; D020869:Gene Expression Profiling; D006790:Host-Parasite Interactions; D006867:Hydrolases / Q000378:metabolism; D007111:Immunity, Cellular; D019476:Insect Proteins / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000254:growth & development / Q000276:immunology / Q000469:parasitology; D008297:Male; D008969:Molecular Sequence Data; D020543:Proteome; D017422:Sequence Analysis, DNA; D015842:Serine Proteinase Inhibitors / Q000302:isolation & purification; D018411:Spodoptera / Q000187:drug effects* / Q000254:growth & development / Q000276:immunology / Q000469:parasitology; D014862:Wasp Venoms / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D014863:Wasps / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology*
chemical_list: D019476:Insect Proteins; D020543:Proteome; D015842:Serine Proteinase Inhibitors; D014862:Wasp Venoms; D006867:Hydrolases