Harnessing ectomycorrhizal genomics for ecological insights.

The ectomycorrhizal (ECM) symbiosis is increasingly seen as a crucial component for nutrient cycling in sustainable forest ecosystems. To date, the complete genome sequence of only a single symbiotic fungus, the ECM basidiomycete Laccaria bicolor, has been released. Its analysis revealed unexpected features, including numerous transposons, secreted effector-like proteins and a lack of carbohydrate-hydrolysing enzymes acting on plant cell walls. Genome-wide transcript profilings showed that most symbiosis-induced transcripts code for proteins with unknown function and identifying their role will be challenging. However, these studies confirmed the key role of membrane transporters in the symbiosis. The analysis of additional genomes from ECM fungi will provide further insights into the evolution, development and ecological role of the mycorrhizal symbiosis.