Host immune suppression by Toxoneuron nigriceps and its associated Bracovirus

The success of parasitism in Hymenoptera is largely influenced by molecules and genes that the ovipositing female injects along with the egg into the host’s body or that offspring produces during the course of development. Here we analyze the functional and molecular bases of the immune suppression syndrome observed in tobacco budworm larvae, parasitized by the braconid wasp Toxoneuron nigriceps. This parasitism-induced alteration is largely mediated by wasp maternal secretions, such a venom and ovarian fluid, which contains the free viral particles of the associated bracovirus (TnBV). The role played by these host regulation factors and of their specific genes is presented, and the first evidence for a functional role played by the non-coding regions of TnBV genome is provided, along with a model taking into account all the available experimental evidences.