Armand Grillon

Research interests

Abiotic stress tolerance in Photorhabdus bacteria

In natural soil ecosystems, bacteria of the genus Photorhabdus (Enterobacterales: Enterobacteriaceae) live in close symbiosis with entomopathogenic nematodes (EPN) of the genus Heterorhabditis (Rhabditida: Heterorhabditidae). These bacteria are transported by the nematodes and released into the bodies of a wide range of soil-dwelling insects. Once inside, the bacteria produce numerous enzymes and toxins that kill the colonized organism. The soil is a highly heterogeneous environment where the performance of the organisms that live in is greatly influenced by numerous abiotic stresses. Hence, the success of the nematodes and their bacteria depends on their ability to adapt and cope with the different abiotic stressors they encounter in the soil. The aim of my master's thesis is to evaluate the impact of different environmental stresses, mostly temperature, pH and reactive oxygen species (ROS) levels, on the growth of different bacterial strains of the genus Photorhabdus. A correct understanding of such a phenomenon is thus essential and would allow us to identify species with potential beneficial adaptations to these abiotic stresses and that could be better biological agents against agricultural pests.