The role of the wasp endocrine system in regulating Bracovirus replication

Endogenization of foreign genetic material from viruses has given rise to new traits in a number of eukaryotes. Among the most unique examples of virus endogenization is the integration of an ancient betanudivirus into the genome of a parasitoid wasp that gave rise to bracoviruses (BVs). BVs are vertically transmitted through the germ line of wasps while specifically replicating in the reproductive tract of females: producing replication-defective virions that wasps inject into hosts with eggs. BV functions in hosts enable wasp offspring to successfully develop. How wasps restrict BV replication to the reproductive system of females is unknown although correlational data suggest an important role for the endocrine system. In this study, we examined the role of endocrine factors controlling development of Microplitis demolitor in replication of M. demolitor bracovirus (MdBV). We report expression profiles of MdBV early and late genes in relation to transcription of hormone response elements. We also report results from gain- and loss of function experiments linking M. demolitor development to the MdBV replication cycle. Overall, our results increase understanding of how wasps domesticated a betanudivirus for functions in parasitizing hosts.