Associate Professor University of Georgia Athens, Georgia
As a parasitoid, the braconid wasp, Microplitis demolitor, has a unique life history where eggs are deposited into live larval hosts alongside viral particles produced in the ovaries of the wasp. This endogenized beneficial virus, Microplitis demolitor Bracovirus (MdBV), combats the larval host immune system while wasps develop inside. The viral-derived genes are contained within the M. demolitor genome and are expressed at different times across the wasp’s development as the virus replicates within the wasp. This includes both early and late transcribed viral genes, where some of the “early” genes encode subunits of a viral RNA polymerase. In related baculoviruses, the RNA polymerase transcribes “late” genes that are responsible for structural virus proteins. It is hypothesized that the viral RNA polymerase function has been conserved in MdBV, and this is supported by previous qPCR studies demonstrating that the knockdown of “early” genes lef-4 and lef-9 reduces transcription of two “late” genes in M. demolitor. This study characterizes genes transcribed by the viral RNA polymerase through RNA-Seq analyses comparing both lef-4 and lef-9 knocked-down datasets to control samples. Results find that when these RNA polymerase subunits are knocked-down, late viral genes are generally downregulated, suggesting that these are likely controlled by the viral RNA polymerase. The function of viral RNA polymerase is shown to be at least partially conserved in regulating the transcription of viral genes in M. demolitor. These findings are under further analysis and are expected to add knowledge to greater themes of viral control in parasitoid literature.
