The successful parasitism by a parasitic insect wasp of its host insect is dependent upon the transfer and expression of a polydnavirus along with the parasite's egg during oviposition. The virus and its life cycle are unique in two major aspects: 1) it is a DNA animal virus with a complex multipartite genome consisting of at least 28 doublestranded, covalaently closed DNAs; 2) the virus has an apparent symbiotic relationship with the wasp insect and causes certain changes in the parasitized host effectively compromising the host's cellular immune defenses to favor the successful development of the parasite. The parasitic Campoletis sonorensis wasp, its virus (CsV), and the host insect, Heliothis virescens, is the most thoroughly studied parasite-virus-host system at the molecular level. Studies will be continued on mapping the genetic organization of the multipartite genome. This will be done by physical mapping and a mapping of the transcription products in the wasp insect and parasitized host. Once mapped those genes believed to be important factors interfering with the parasitized insect's cellular defense system will be cloned and studied for function and identity of viral encoded gene products. It is the ultimate goal of the research to identify the specific functions of the virus and mechanisms (target sites and effects) in the parasitized insect abrogating cellular immune response. This should lead to an elucidation of insect immunity defenses and how these may be manipulated for the control of insects of public health or agricultural importance, or for control of the ability of insects to transmit animal and plant pathogens.
