The constituents of Microctonus sp. parasitoid venoms

Abstract

Purified RNA transcripts from venom glands dissected from the parasitoid wasp Microctonus hyperodae were copied, cloned and sequenced using traditional dideoxy sequencing methods. Using mass spectrometry analysis of the trypsinised PAGE gel protein bands we identified the RNA transcripts for the 3 most abundant proteins found in the venom and hence obtained their full protein sequence. Other abundant transcripts were also further sequenced. To reduce the effort required to obtain transcript information we dissected venom glands from a second parasitoid, Microctonus aethiopoides (Morocco biotype). The RNA transcripts were purified and reverse transcribed but instead of cloning the cDNA it was directly sequenced using Roche GS20 pyrosequencing. Results from a single GS20 sequencing run provided data similar to that obtained by the traditional methods used in analysing transcripts from M. hyperodae in a fraction of the time and cost. Comparing the transcripts between the two species showed that a similar range of genes are expressed with the putative orthologs of seven of the eight full length genes characterised from M. hyperodae being found in M. aethiopoides. Pyrosequencing should provide a valuable new method for rapidly sampling transcripts from a wide range of specialised insect tissues.

Comparative venomics of Psyttalia lounsburyi and P. concolor, two olive fruit fly parasitoids: a hypothetical role for a GH1 β-glucosidase

“…Among these, a family of five related proteins contains a signal peptide and the DUF4803 domain of unknown function (Supplementary Figure S3). They share similarities with venom proteins of the braconids C. inanitus 11, M. demolitor 12 and M. hyperodae 20, and of N. vitripennis 21.…”

Identification of the main venom protein components of Aphidius ervi, a parasitoid wasp of the aphid model Acyrthosiphon pisum

“…Although typically membrane-bound, ectopeptidases such as NEP may also be shed from the membrane through a proteolytic process and found in the surrounding fluid [47]. NEP-like proteins were detected in the venom of the parasitoids L. boulardi [18], Microctonus hyperodae [19], H. didymator [20] and M. demolitor [17], and were also found associated with the VLPs produced in the ovary of V. canescens [48]. Although the role of soluble ectopeptidases is still not understood, NEP-like proteins have been hypothesized to modulate the host immune system by degrading immune-specific peptides [48].…”

“…Comparison of venom data sets for A. ervi and PDV-associated braconid wasps, such as Chelonus inanitus [25], Microctonus sp. [19] and Microplitis demolitor [17], will provide insights on how the use of various parasitism strategies impacts venom evolution. Although we identified a large number of transcripts and proteins, we have focused our analysis on the major venom components since they are the most likely involved in parasitism success [18, 20].…”

Extracellular Superoxide Dismutase in Insects

“…A likely role of L. boulardi venom SOD3 in parasitism success is supported by the specific overexpression of the sod3 gene in the venom apparatus compared with other tissues, as shown for most parasitoid virulence factors (43)(44)(45)(46)(47)(48)(49)(50)(51)(52), including two major venom toxins of L. boulardi (17,19). In L. heterotoma, the SOD3 protein is hardly detected in venom, and the venom contains no measurable Cu,Zn-SOD-specific activity.…”