News
Nasonia vitripennis used as model for improving biocontrol agent performance and reducing their environmental impact
ESR update - Making agents more effective at controlling pests, easier to mass culture, and less likely to harm non-target species are major goals of biocontrol. However, surprisingly little is known about the genetics and genomics underlying these traits. The parasitic wasp Nasonia vitripennis has many genetics tools available, making it an excellent model to study the genetics of improving biocontrol agent performance and reducing their environmental impact.
Parasitoids are one of the most widely used classes of biocontrol agents. I am using Nasonia vitripennis and its relatives, which are parasitoids of blowflies, to study genes underlying important biocontrol related traits in parasitoids. My objective is to characterize the genomics of these traits. Having fully sequenced and annotated genomes available for several Nasonia species is a great help in this venture.
My two focal traits are starvation resistance and host specificity. Starvation resistance is highly relevant to mass culture and field performance, where biocontrol agents often have limited access to food. Shuwen Xia of RP13 and I decided to conduct parallel and complementary studies for this trait to compare phenotype-based artificial selection (me) and genomic-based selection (Shuwen). At the end we will use our results to compare the effectiveness of each method in making Nasonia more starvation resistant, and see if the same genetic network is implicated by the two approaches. The first part of this project was designing an assay that could accurately assess starvation resistance across two different labs. The key was separating the effects of starvation (hunger) from effects of desiccation (thirst).
The second trait, host specificity, was inspired by my interest in the environmental impact of biocontrol. In Hawaii, where I studied for my Masters, biocontrol is highly controversial because it caused the decline of many native species even though it protected the agricultural industry. I wanted to explore how biocontrol agents could be manipulated to be more host-specific and less hostile to non-target species. I was surprised to find out that for Nasonia a host specificity locus is already known. As a generalist, Nasonia vitripennis hosts on many different species, but its specialist relatives parasitize only a single genus of blowfly. In a previous study, introgressing a specific gene region from Nasonia giraulti into vitripennis made the latter more host-specific I am breeding this region from specialist Nasonia longicornis into vitripennis to see if it also causes a change in host specificity. I also plan to “knock down” this gene using RNAi, which will make it non-functional. My hypothesis is that this gene helps wasps detect olfactory cues from the host, so knocking it down will prevent specialists from being able to distinguish different host species. This research may therefore be the key to understanding how host specificity of biocontrol agents can be altered to our benefit.
In between work I have been settling in happily in the Netherlands with the help of my advisors Leo Beukeboom and Louis van de Zande, and all my labmates. It has also been a delight becoming friends with all the ESRs, and spending time together in each others’ host cities.