Understanding the molecular interplay between bacterial pathogens and hosts : an evolutionary approach

Abstract

The emergence of ecological adaptations is a fundamental conundrum in evolutionary biology. A magnificent and astonishing diversity of life forms occupy a myriad of ecological niches, from stable intra-cellular nutrition-rich environments to harsh ones. How do these forms emerge? The aim of my PhD is to contribute to unearthing the evolutionary rules of ecological innovation by focusing on particular sets of molecules that mediate the interaction of organisms with the environment. We focused on the understanding of two questions: (i) what is the role of secretion systems in the emergence of ecological adaptations in prokaryotes, and in particular in pathogenic bacteria? and (ii) how does the environment react to these adaptations, particularly how do hosts counteract the different adaptation mechanisms of pathogens? The interplay between the plasticity of the environment, be it a chemical environment or an organism with a greater biological complexity, and that of the occupying organisms has generated a complex dynamic of evolution and counter-evolution responsible for the great biological diversity we see today on Earth.