Experimental evolution in a tri-factorial system

Objectif

Parasitic nematode infections are a major threat to human, animal and plant health. Infection prevention or control depends heavily on chemical treatment, but resistance is becoming widespread, and the compounds used pollute surface- and groundwater. To develop new mitigation strategies, it is important to understand host-parasite interactions and fundamental mechanisms of parasitism, but parasites of vertebrates are difficult to study. Entomopathogenic nematodes (EPNs) and their hosts offer great potential in this context. EPNs are microscopic nematodes that prey on larval stages of many insects and naturally help regulate insect populations. EPNs are commercially available to target a range of soil-dwelling plant pests, but efficiency depends on the environment and the targeted pest. EPNs have also been used to study immunological responses of insect hosts. In these studies, a fraction of the hosts survives the infection. The aim of research proposed here is to select the surviving hosts and establish a model system of the EPN-host complex to study host-parasite interactions through experimental evolution of parasitism. Traits including life span and stress responses, as well as genomic and transcription changes of the host and the EPN will be studied. The downstream application of this model is the optimization of biocontrol agents of plant and animal pathogens by selecting EPNs that are resistant to environmental stressors like heat, desiccation and UV radiation, and that prey on new host species. The proposed research uses the EPN Heterorhabditis bacteriophora, its symbiont Photorhabdus luminescens, and the host Drosophila melanogaster. The expertise of the supervisor in Drosophila and evolutionary research combined with the Experienced Researcher’s (ER) empirical and computational skills provides a perfect match for the proposed project. Additionally, the project will integrate the ER’s multidisciplinary skillset for a future career as an independent academic.