As the picture above, my recent research has been focusing on interactions. However, not between two individuals of the same species but among highly distantly related species. Indeed during my PhD I have been focusing on one of the most widely spread symbiosis in terrestrial ecosystems, the arbuscular mycorrhizal fungal (AMF) symbiosis. Which consist in a high degree of co-adaptation between a highly specialized fungus, the AMF, and around 75% of terrestrial plants. In this context, I have studied the genomics diversity of this important symbionte (Savary et al., 2017, The ISME journal) in order to understand from the point of view of population, the surprising phylogeographical pattern observed in these microbes. We confirmed previous though of a large dispersion of almost clonal individuals. In this studied we also uncovered a diversity within the model fungus of the AMF, R. irregularis, with possible several cryptic species. Such findings could suggest that we underestimate with the current molecular tools the real diversity of these ecologically important fungi. In a second study in preparation, we have studied the role of this newly discovered diversity on the plant transcriptomic response. Interesting results will be soon available (Savary et al. in prep.).