Protein discovery: combined transcriptomic and proteomic analyses of venom from the endoparasitoid Cotesia chilonis (Hymenoptera: Brachonidae)

Authors: TENG, ZI-WEN - Zhejiang University; XIONG, SHI-JIAO - Zhejiang University; XU, GANG - Zhejiang University; GAN, SHI-YU - Zhejiang University; CHEN, XUAN - Zhejiang University; Stanley, David; YAN, ZHI-CHAO - Zheijiang University; YE, GONG-YIN - Zheijiang University; FANG, QI - Zheijiang University

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2017
Publication Date: 4/12/2017
Citation: Teng, Z., Xiong, S., Xu, G., Gan, S., Chen, X., Stanley, D.W., Yan, Z., Ye, G., Fang, Q. 2017. Protein discovery: combined transcriptomic and proteomic analyses of venom from the endoparasitoid Cotesia chilonis (Hymenoptera: Brachonidae). Toxins. https://doi:10.3390/toxins9040135.
DOI: https://doi.org/10.3390/toxins9040135

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 biological control of insects is a potentially powerful alternative to classical insecticides, 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, by identifying new venom-specific proteins in the parasite. We learned that these proteins will guide continued research into how these proteins influence the narrow range of hosts in the parasite. Scientists who study host/parasite relationships will use this information in research designed to 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: Background: Many species of endoparasitoid wasps provide biological control services in agroecosystems. Although there is a great deal of information on the ecology and physiology of host/parasitoid interactions, relatively little is known on the protein composition of venom and how specific venom proteins influence physiological systems within host insects. This is a crucial gap in our knowledge because venom proteins act in modulating host physiology in ways that favor the parasitoids. Our aim here was to begin filling the gap by identifying protein components of the polydnavirus (PDV)-carrying endoparasitoid Cotesia chilonis by combining transcriptomic and proteomic analyses. Results: We identified 29 possible venom proteins. The most abundant proteins were hydrolases, such as proteases, peptidases, esterases, glycosyl hydrolase and endonucleases. Some components are classical parasitoid venom proteins with known functions, including extracellular superoxide dismutase 3 (SOD3), serine protease inhibitor and calreticulin (CRT). The venom preparations yielded additional novel proteins, not recorded from any other parasitoid species, such as tolloid-like proteins (TLPs), chitooligosaccharidolytic ß-N-acetylglucosaminidase (NAG), FK506-binding protein 14 (FKBP14), corticotropin-releasing factor-binding protein (CRF-BP) and vascular endothelial growth factor receptor 2 (VEGFR2). Conclusions: The C. chilonis venom is a complex mixture of components including a previously unappreciated range of proteins. This bioinformatic analysis supports our reports of research at the physiological level: venom is an essential element of successful parasitoid biology. These new data provide a platform for functional analysis of venom components.