Endosymbiotic associations between plants and soil microorganisms play key roles in improving the supply of essential nutrients such as nitrogen and phosphorus to the host plant. Our team focuses on important symbiotic associations involving either arbuscular mycorrhizal (AM) fungi or nitrogen-fixing bacteria (Rhizobium/Frankia) hosted in specialized root organs known as nodules of either legume or actinorhizal plant species. The model legume Medicago truncatula is used primarily to investigate the molecular and cellular mechanisms underlying early microbe-host signaling and endosymbiotic infection, as well as the cell differentiation that takes place during root nodule development. Research conducted in our team has contributed to the development of new tools for studying root symbioses at the cell/tissue level. This includes genome-wide tissue-specific transcriptomics for gene expression profiling as well as in vivo confocal imagery techniques for studying cell-specific responses during host-microbe communication and root infection. These tools have also proved invaluable for the functional characterization of several key symbiotic transcription factors (TFs) involved in host-microbe signaling, infection and nodule development. The principal team projects are outlined in the 'research themes' pages under the following headings: (I) Microbial Signaling and Host Cellular Dynamics Associated with Endosymbiotic Infection, (II) Cell Reprogramming for Infection by Beneficial Symbiotic Partners, (III) NF-Y TFs: Key Regulators of Infection & Nodule Development and (IV) Control of nodule differentiation.