Venom proteome of the parasitoid wasp Theocolax elegans
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ABSTRACT: venom proteins from Theocolax elegans were analyzed by LC-MS/MS and the peptide fragments were identified by searching against the protein set.
Project description:For many behaviours studied at the phenotypic level, we have little or no idea of where to start searching for “candidate” genes: the transcriptome provides such a starting point. Here we consider transcriptomic changes associated with oviposition in the parasitoid wasp Nasonia vitripennis. Oviposition is a key behaviour, as females are faced with a variety of decisions that will impact offspring fitness. These include choosing between hosts of differing quality, as well as deciding on clutch size and offspring sex ratio. We compared the whole-body transcriptomes of resting or ovipositing female Nasonia using a “DEEP-Sage” gene expression approach on the Illumina sequencing platform. Single 2-day old mated Nasonia vitripennis females (ASymC strain) were isolated in a glass vial and provided with a single host to produce F1 daughters. Eight 2-day old mated F1 females were subsequently provided with three hosts to produce the F2 test females. We randomly selected one host from each F1 female, and isolated 16 2-day old mated F2 test females in glass tubes, of which eight were randomly allocated to the oviposition treatment and eight to the resting treatment. We provided the test females with a single host for 24 hours as pre-treatment to facilitate egg development. We then discarded the pre-treatment hosts and gave each female a piece of chromatography paper soaked in honey solution for a further 24 hours. For the experiment, we transferred the females to 1.5 mL Eppendorf tubes that contained a single host for the oviposition experiment, or were empty for the resting treatment. After 60 mins, females were flash-frozen in liquid nitrogen and stored on dry-ice until the addition of RNAlater-ICE (Ambion, Austin, TX, USA) after which they were transferred to -20C. All females in the oviposition treatment were observed to have commenced ovipositing. We pooled the F2 test females from each F1 mother according to treatment, generating a total of eight pooled samples per treatment (consisting of 8 females per pool) for RNA isolation and sequencing.
Project description:This project aims at characterizing the molecular basis of virulence difference between two strains of the Hymenopteran parasitoid Cotesia typhae, which differ in their parasitism success on one host population. More specifically, we analyzed the protein content of the venom of both strains in order to quantify abundance differences in key virulence proteins.
Project description:The composition and biotic nature of wasp VLPs has remained uncharacterized. VLP proteomics have contributed to a new understanding of their unusual organelle nature and mechanism of action in suppressing host defense responses.
Project description:The composition and biotic nature of wasp VLPs has remained uncharacterized. VLP proteomics have contributed to a new understanding of their unusual organelle nature and mechanism of action in suppressing host defense responses.
Project description:Gene duplication, accompanied by modification of the expression and/or function of one of the duplicates under the action of positive selection, followed by further duplication to produce multigene families of toxins is a well-documented process in venomous animals. This evolutionary model has been less described in parasitoid wasps, which use maternal fluids, including venom, to protect their eggs from encapsulation by the host immune system. The leptopilina venom proteomic data were used to evidence that specific RhoGAPs formed a family of protein that are associated with vesicles that act as transport systems to deliver them in the immune cells of their drosophila larval host. We showed that the gene encoding the cellular RacGAP1 is at the origin of the virulent RhoGAP family formed by successive duplications that evolved under positive selection. Almost all of these RhoGAPs lost their GAP activity and GTPase binding ability due to mutations in key amino acids suggesting new function(s) and mechanism of action in host cells that remain to be elucidated.
Project description:Upon pathogenic infection, drosophila larval host mounts an immune response. Parasitic wasps inject venom that contain virulence factors during oviposition, which can elicit host immune response, and in some cases, suppress host immune responses altogether. Several microarray experiments have been performed on different classes of parasitic wasps. We wanted to compare how Ganaspis xanthopoda-infected hosts respond compared to other classes of parasitic wasps. Third instar y w larvae from a 2-day egglay were infected with G. xanthopoda for three and six hours, respectively, by introducing waps in petri-dish containing larvae. Controls were handled side-by-side without introducing wasps. Host larvae were immediately dissected, infection confirmed by presence of wasp egg, and frozen in liquid nitrogen and ground in Trizol. RNA was isolated and checked by agarose gel-electrophoresis. Samples were then sent to the Microarray Core Facility at Weill Cornell Medical College.
Project description:Linking the evolution of the phenotype to the underlying genotype is a key aim of evolutionary genetics and is crucial to our understanding of how natural selection shapes a trait. Here we consider the genetic basis of sex allocation behaviour in the parasitoid wasp Nasonia vitripennis using a transcriptomics approach. Females allocate offspring sex in line with Local Mate Competition (LMC) theory. Female-biased sex ratios are produced when one or few females lay eggs on a patch. As the number of females contributing offspring to a patch increases, less female-biased sex ratios are favoured. We contrasted the transcriptomic responses of females as they oviposit under conditions known to influence sex allocation: foundress number (a social cue) and the state of the host (parasitised or not). We found, that when females encounter other females on a patch, or assess host quality with their ovipositors, the resulting changes in sex allocation is not associated with significant changes in whole-body gene expression. We also found that the gene expression changes produced by females, as they facultatively allocate sex in response to a host cue and a social cue, are very closely correlated. We expanded the list of candidate genes associated with oviposition behaviour in Nasonia, some of which may be involved in fundamental processes underlying the ability to facultatively allocate sex, including sperm storage and utilisation. 2 x 3 factorial design. Females were placed into 1 of 2 "foundress number" groups: 1) alone or 2) in the presence of 9 other females (co-foundresses). Females were further subdivided into host treatment groups: i) given no host, ii) given a fresh host and iii) given a pre-parasitised host. This gives a total of 6 possible treatment combinations. For each of these 6 groups, 7 pools of 10 females were sequenced giving 42 libraries altogether.
Project description:The purpose of this project was to identify venom proteins from the venom gland of Ganaspis hookeri (strain GhFl, formerly 'G1'), a parasitoid wasp species that infects fruit flies in the genus Drosophila.