I am an evolutionary biologist working on the evolution of plant-microorganisms interactions. I have developed and used large scale integrative approaches of phylogenomics to decipher the genetic mechanisms regulating the beneficial interactions between plants and microorganisms like fungi and bacteria. I especially demonstrated the ancestral state of the genetic mechanisms regulating the arbuscular mycorhizal symbiosis in all land plants. In the frame of the ENSA consortium, I reconstructed, using phylotranscriptomics approach, the ancestral transcriptome of the first plant able to associate with nitrogen-fixing bacteria and identified that all crucial genes were likely deregulated during in this ancestor. Based on this, I performed detailed phylogenetic anaysis of candidate genes to drive the functional validation, leading to the identification and characterization of new key players in the nitrogen-fixing symbiosis. Finally, I investigated the evolution of the capacity of certain algae to form lichens with fungi. I confirmed that this interaction is the results of a convergent evolution and identify key genes of this interaction such as a glycolyse hydrolase horizontally acquired in lichen-forming algae that could regulate the cell-wall modifications during the interaction. Overall, my large scale integrative phylogenomics approaches are powerful tools to identify, understand the evolutionary history and orient the functional validation of promising candidate genes associated with a given trait. In the department of insect symbiosis at Max Planck Institute, I will used such integrative phylogenomic approaches to decipher the beneficial symbiosis between insects and microorganisms like bacteria and fungi.