One PhD project (WPD1-3) will focus on the relative importance of gut microbial communities and native insect enzymes in the detoxification of GSL breakdown products by two specialist Delia species feeding on Brassica roots. We will test the hypothesis that these congeners, feeding on the same host plants with similar chemical defences rely on their native detoxification enzymes combined with those of the gut microbiome to optimize their performance on GSL-containing hosts. By using an integrated experimental-ecogenomics approach we will identify which of the detoxification enzymes in either the insect or the microbiome are essential for the insect’s performance on GSL-containing diets.

The second PhD project (WP M1-3) will focus on the contribution of glucosylation to GSL detoxification in the piercing-sucking insect Myzus persicae. Using a mixture of molecular biology, analytical chemistry, ecology and biochemistry approaches, we will identify the enzymes responsible for these reactions, and test the hypothesis that these benefit the insect when feeding on dietary GSLs. Further, we will determine whether manipulating these activities in vivo will have ramifications extending to associated organisms, unbalancing the aphid interactions with its gut microbiota, higher trophic levels, and competing insects and pathogens.

Together, these projects will contribute to enhancing our knowledge of how chemical defenses against herbivores cascade through trophic levels above- and belowground, and will make an important contribution towards understanding how plant GSL mediate processes in complex biosystems.