Parasites frequently cause their host to show developmental and biochemical abnormalities which disturb the normal growth and reproduction of the organism. Some effects appear to be mediated by factors associated with the parasites such as bacteria or viruses, in addition to the parasites themselves and the stress invoed by their feeding and consumption of host nutrients. Using the tobacco hornworm and a braconid wasp parasite as a model system, Dr. Beckage has shown that a virus injected by the parasite into the host stimulates biosynthesis of novel proteins found only in parasitgized larvae. The goal of this grant will be to characterize the proteins involved and study their regulation to determine if the genes encoding for their synthesis are components of the host, parasite, or viral genome (s) and clarify the mode of their induction. The tissues producing the proteins will be identified and the physiological role of the proteins will be studied to gain fresh insights into the developmental dynamics of how the physiology of the host is modulated to facilitate successful parasitism. This parasitic wasp, Cotesia congregata, serves as"a biological control of several insect pests, and many closely related species are similarly important in agricultural and forest ecosystems. Thus the information gained from this study may have important implications for design of novel strategies to control a variety of insect pests in addition to serving as a valuable parasitological model which will enhance our understanding of the mechanisms involved in regulation of host physiology at txe host-parasite interface. Biotechnology could be used to express normally parasitism-specific genes in the unparasitized state, for example, causing developmental arrest prior to reproduction.
