Donnerstag, 13. März 2014
16 Uhr, HS 7 (Carl-Zeißstr. 3)
Vortragender: Dr. Martin Kaltenpoth (Max Planck Institute for Chemical Ecology, Research Group Insect Symbiosis, Jena, Germany)
Titel: A perfect drug deal: Evolution, ecology, and genomics of symbiont-mediated antibiotic defense in solitary wasps
Mutualistic microorganisms play a key role for nutrition or pathogen defense in many animals. A group of solitary digger wasps, the "beewolves" engage in a unique protective symbiosis with Streptomyces bacteria that they cultivate in specialized glands in their antennae and transfer to the larval cocoon. Within the first two weeks after cocoon-spinning by the beewolf larva, the symbionts produce a complex cocktail of antimicrobial compounds, thereby efficiently protecting the larva against fungal and bacterial pathogens during the long period of hibernation in the cocoon. Phylogenetic analyses of hosts and symbionts indicate that the symbiosis already evolved in the Cretaceous. Although the bacteria can be exchanged among host species, beewolves ensure specificity in the association by controlling symbiont transmission, which resulted in the stable and long-term symbiosis with a single clade of symbionts. In the symbionts of the European beewolf, the intimate association with the host has resulted in the accumulation of frameshift mutations in the genome, indicative of ongoing erosion of the genetic material and increasing dependence on the host. The genes involved in antibiotic production, however, remain intact and fully functional. Chemical characterization of the symbiont-produced antibiotic cocktail across beewolf species revealed a high degree of conservation, indicating that the complex mixture serves as an efficient and evolutionarily stable long-term defense. Thus, by means of their symbionts, beewolves employ a strategy comparable to the combination treatment used in human medicine to successfully fend off a broad range of detrimental microorganisms and to prevent the evolution of resistant pathogens.