Venomics of the ectoparasitoid wasp Bracon nigricans

Abstract

Background: Venom is one of the most important sources of regulation factors used by parasitic Hymenoptera to redirect host physiology in favour of the developing offspring. This has stimulated a number of studies, both at functional and "omics" level, which, however, are still quite limited for ectophagous parasitoids that permanently paralyze and suppress their victims (i.e., idiobiont parasitoids). Results: Here we present a combined transcriptomic and proteomic study of the venom of the generalist idiobiont wasp Bracon nigricans, an ectophagous larval parasitoid of different lepidopteran species, for which we recently described the host regulation strategy and the functional role of the venom in the induction of physiological changes in parasitized hosts. The experimental approach used led to the identification of the main components of B. nigricans venom involved in host regulation. Enzymes degrading lipids, proteins and carbohydrates are likely involved in the mobilization of storage nutrients from the fat body and may concurrently be responsible for the release of neurotoxic fatty acids inducing paralysis, and for the modulation of host immune responses. Conclusion:The present work contributes to fill the gap of knowledge on venom composition in ectoparasitoid wasps, and, along with our previous physiological study on this species, provides the foundation on which to develop a functional model of host regulation, based both on physiological and molecular data. This paves the way towards a better understanding of parasitism evolution in the basal lineages of Hymenoptera and to the possible exploitation of venom as source of bioinsecticidal molecules.

Review of Venoms of Non-Polydnavirus Carrying Ichneumonoid Wasps

“…This is a huge cosmopolitan subfamily whose members are mostly idiobiont ectoparasitoids of holometabolous insect larvae. The venom of only one species, Habrobracon hebetor , has been investigated in any detail, with a few studies also on H. brevicornis , H. gelechiae [ 156 ], H. nigricans [ 51 , 157 ] and Bracon mellitor [ 117 ]. As regards work published as having been carried out on H. hebetor , it should be noted that there has been some taxonomic confusion so it is possible that some laboratories were actually working on the related H. brevicornis that was for a long period treated as a junior synonym of hebetor [ 158 ].…”

“…Recently, proteotranscriptomics has been applied to the venom of another closely related braconine, Habrobracon nigricans (as Bracon ), which among other hosts can be cultured on Spodoptera littoralis [ 51 ]. Venom proteins were separated on SDS-PAGE gels ( Figure 11 ), and protein bands excised and identified using LC/MS-MS. A summary of the identified and putatively identified venom proteins is shown in Table 5 .…”

“…Left hand lane (M) shows protein molecular weight markers, right hand lane shows venom (V) proteins. (Source from [ 51 ] under the terms of Creative Commons Attribution Licence CC-BY 4.0 via BMC Genomics ).…”

A salivary chitinase of Varroa destructor influences host immunity and mite’s survival

“…These results are well in tune with the available evidence reporting that ticks and parasitoid wasps, as well as other venomous animals can secrete and inject into the host similar virulence factors to subdue them and/or redirect their physiology. Examples of this convergence are represented by phospholipases A 2 [31,32], serine protease inhibitors [33]…”

“…near curvimaculatus (GenBank: AAA61639.1), T. nigriceps (GenBank: AAX69085.1) and N. vitripennis (GenBank: NP_001128139.2). Protein sequences were aligned and phylogeny reconstruction was carried out as reported elsewhere [31].…”