Research Group Sequestration and Detoxification in Insects

Phyllotreta leaf beetle

The vast majority of insect herbivores feed only on a limited number of plant species. This dietary specialization is often directly linked to their evolutionary adaptation to the plants’ chemical defenses. Common strategies to cope with noxious plant metabolites include rapid excretion, enzymatic detoxification, and sequestration. Some insects are even able to exploit these compounds for their own defense against predators. In most cases, however, the underlying mechanisms are unknown.

Our focus is on the interaction between crucifer-feeding flea beetles and their host plants. Nearly all Phyllotreta species (> 200 species world-wide) are specialists on plants in the order Brassicales, and some species are devastating pests of crucifer crops such as cabbage and canola. The characteristic secondary metabolites of Brassicaceae are the mustard oil glucosides, so called glucosinolates. Upon tissue damage they are degraded by the plant enzyme myrosinase. This triggers the release of reactive isothiocyanates which are responsible for the spicy taste of wasabi and mustard. Phyllotreta leaf beetles are able to disarm this “mustard-oil bomb” and selectively sequester intact glucosinolates from their host plants. With this background, we seek to answer the following questions: (1) how do Phyllotreta beetles prevent glucosinolate hydrolysis by the plant myrosinase? (2) in which tissue are glucosinolates stored and is there evidence of further metabolism in the beetle? (3) do sequestered glucosinolates play a role in defense against predators and/or assortative mating? We address these questions using molecular and biochemical tools, analytical chemistry, as well as behavioral ecology.

Group Leader:

Dr. Franziska Beran
+49 (0)3641 57 1553