séminaire du pôle évolution du vivant – vendredi 12 avril 2013

Evolution of host-pathogen interactions in the model nematode host Caenorhabditis elegans

Hinrich Schulenburg, université de Kiel (Allemagne)

vendredi 12 avril 2013 à 11 heures, amphithéâtre Mariotte

 

The Red Queen hypothesis predicts that host-pathogen interactions associate with extremely high selection dynamics. These selective pressures result in fast and complex changes in both antagonists. We study the complexity of changes using the model nematode host Caenorhabditis elegans and various pathogens such as Bacillus thuringiensis and Pseudomonas aeruginosa. We have established an experimental evolution approach, which allows us to study evolution in real-time under controlled laboratory conditions. During my talk, I will provide an overview of our recent results, which show that host-pathogen coevolution causes (i) complex phenotypic changes in both antagonists, (ii) an increased evolutionary rate and also biodiversity in both antagonists, (iii) a pronounced difference to the consequences of one-sided adaptation (i.e., only one antagonist evolves, whereas the other does not), and (iv) a selective advantage of outcrossing and horizontal gene transfer. We also used whole-genome sequencing to demonstrate the importance of multiple genetic changes during coevolutionary adaptation. In concordance with the Red Queen, our experimental findings thus highlight the enormous selective power of host-pathogen interactions, which likely represent a central driver of evolutionary diversification.