Location: Biological Control of Insects ResearchTitle: Parasitization by Scleroderma guani influences protein expression in Tenebrio molitor pupae) Author
Submitted to: Journal of Insect Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/12/2014
Publication Date: N/A
Citation: Interpretive Summary: Long-term agricultural sustainability is severely threatened by widespread use of classical insecticides. Threats include increasing resistance to insecticides and sharply decreasing environmental quality. The concept of biological control of insects is a potentially powerful alternative to classical insecticides. Biological control is based on the idea that direct application of certain insect-specific predators, pathogens and parasites can reduce pest insect populations to a point that the pests exert only negligible economic damage. A major problem, however, is that many insect parasites have a very narrow range of hosts. This limits the usefulness of any given parasite species in biological control programs. In this paper, we examined the relationship of a parasitic insect and its host, a pest insect. We learned that venom from the parasite is essential to the success of the parasite. Scientists who study host/parasite relationships will use this information in future research designed understand how parasite venom can be manipulated to broaden the host range of a parasite. Ultimately, this research will benefit growers who produce vegetable crops and the people who consume vegetables.
Technical Abstract: Ectoparasitoid wasps deposit their eggs on the surface and inject venom into the host. Venoms are chemically complex and they exert substantial impact on hosts, including permanent or temporary paralysis and developmental arrest. These visible venom effects emerge from changes in expression of genes encoding proteins that act in the physiological responses to envenomation. While the influence of parasitization on gene expression in several lepidopterans has been reported, there is very little information on parasitoid/beetle relationships. This shortcoming led us to pose the hypothesis that envonomation by the ectoparasitic ant-like bethylid wasp Scleroderma guani leads to substantial changes in protein expression in the yellow mealworm beetle Tenebrio molitor. We tested our hypothesis by comparing the proteomes of non-parasitized and parasitized host pupae using iTRAQ-based proteomics. We identified 41 proteins that were differentially expressed in parasitized pupae, of which 32 were up-regulated and 9 were down-regulated. Of these, we identified the defense proteins, serine protease and its inhibitor, glutathione S transferase, superoxide dismutase, peroxiredoxin, the energy enzymes, tenebrin, and translationally controlled tumor protein. We assigned these proteins to functional categories, including immunity, stress and detoxi'cation, energy metabolism, development, cytoskeleton, signaling and others. At the transcriptional level, we selected 14 differentially expressed protein genes for analysis by quantitative real-time PCR. We recorded parallel changes in mRNA levels and protein abundance following parasitization. Our 'ndings support our hypothesis by documenting substantial changes in protein expression in parasitized hosts and identify specific gene/protein combinations for advanced hypotheses about molecular basis of ectoparasitology.