The Epigenetics of Mycorrhizae – EpiMyc

An intrinsic characteristic of trees from boreal and temperate forest ecosystems is the mutualistic association with soil-borne ectomycorrhizal (ECM) fungi in their roots. ECM fungi provide trees with nutrients while in return they receive photosynthetically-derived carbon. These exchanges improve tree nutrition and consequently growth and performance. While the molecular events leading to this mutualist interaction have been described, the role of epigenetics in the establishment and modulation of mutualistic interactions such as mycorrhization remains to be established. A recent publication from our consortium suggests that several host and fungal genes involved in the mutualistic interaction are under epigenetic control, highlighting a new level of gene regulation to already complex interactions. EpiMyc aims to establish the causality between epigenetic variations in tree or fungus and the recognition, establishment and functioning of mycorrhization. EpiMyc will merge experimental and computational disciplines into an integrative approach exploiting the well-established model tree system Poplar (Populus spp.) and the ectomycorrhizal fungal Laccaria bicolor. EpiMyc brings together specialists on mycology, tree ecophysiology and (epi)genomics in order to: i) Disentangle constitutive and inducible epigenetic changes during mycorrhization establishment and see how findings can be extended to the establishment of root microbiota, ii) Test the natural genetic variability of tree populations for their ability to establish ectomycorrhization and identify associated (epi)genomic variations, iii) Evaluate the plasticity and biological significance of the ECM association under water deficit and iv) Carry out an integrative analysis modeling the multiscale relationships between mycorrhization characteristics and their molecular determinants and functional validation of candidate genes using genome edition.