Speaker
Description
Insects represent the most diverse animal class on earth, and their evolutionary success is at least partly due to their ability to engage in manifold interactions with beneficial microorganisms. These symbiotic microbes can live intra- or extracellularly in their insect hosts and provision limiting nutrients, digestive or detoxifying enzymes, or protective chemicals that enhance host fitness. While research of the past decades has uncovered the astonishing taxonomic and functional diversity of insect-microbe associations, the chemical and molecular basis underlying their establishment, maintenance, and transmission remain incompletely understood, especially due to the scarcity of experimentally and genetically tractable intracellular symbioses. Grain pest beetles, especially the saw-toothed grain beetle Oryzaephilus surinamensis, present excellent study systems, as they harbor intracellular symbionts that can be experimentally eliminated without killing the host. Using a combination of chemical analytics, molecular tools and bioassays, we have uncovered the role of the symbionts in the biosynthesis of tyrosine and its impact on the beetle’s cuticle biosynthesis and defense against enemies. Furthermore, we managed to introduce a genetically tractable intracellular bacterium into O. surinamensis that now allows us to study the molecular basis of symbiosis establishment as well as the interaction between the newly introduced bacterium and the ancient endosymbiont. The results provide interesting first insights into the molecular host-symbiont interplay as well as the evolutionary steps leading to the establishment of novel symbioses.
