Secondary Toxicity Mechanisms of Insecticides and Their Metabolism in Pollinators

Insecticides are one of the main stressors faced by pollinators, whose numbers are in global decline. Few studies have been undertaken to profile their secondary effects, that is responses not mediated through primary target interactions. S.cerevisiae, Baker's yeast, offers an ideal model for characterising secondary insecticide effects as its genome lacks their main molecular targets, whilst at the same time sharing fundamental cellular processes with other eukaryotes. Gene expression analysis will be conducted to reveal insecticide mediated responses in yeast for twelve insecticides, representing five classes. These results will be combined with existing, analogous expression studies in the bumblebee, B.terrestris, to identify homologous secondary responses. Gaining a holistic understanding of insecticide toxicity mechanisms is crucial for assessing their risk to pollinators.
The second part of this project will aim to map the enzymes responsible for insecticide metabolism in B.terrestris. Using S.cerevisiae based expression systems, cytochrome p450 enzyme (CYP) driven insecticide metabolism will be evaluated, with individual CYP substrate profiles determined. In turn, CYPs important to metabolism will become the basis for a phylogenetic comparison study, to assess the capability of insecticide metabolism in distantly related pollinator species. This presents the first step to predictive detoxification profiling.