Viewpoint: A new lens on ectomycorrhizal function: exploring the absorber-miner spectrum

Mycorrhizal symbiosis is widespread in nature, occurring in approximately 90% of terrestrial plant species, and played a crucial role in enabling plant colonization of land over 450 million years ago. The majority (>80%) of these associations are formed by endomycorrhizae, in which fungi from the phylum Glomeromycota penetrate the cortical cells of host plant roots, forming branched hyphal structures that facilitate nutrient exchange. These fungi associate with a wide range of angiosperms, including major crops. In contrast, ectomycorrhizae, which colonize the apoplastic regions of the epidermal and cortical cells, are formed by relatively fewer plant species—primarily trees—but dominate vast areas of the forests. Although mycorrhizal symbiosis is critical to ecosystem function, generalizing their ecological roles, species distributions, and organismal traits remains a challenge. Jörgensen and colleagues propose a stoichiometric model linking nitrogen flux with ectomycorrhizal traits. By conceptualizing fungal lifestyles along a continuum from “absorbers” to “miners,” the model predicts various aspects of ectomycorrhizal ecophysiology—including morphological, physiological, metabolic, and resource acquisition traits—based on their position along this spectrum. Absorbers exhibit high carbon use efficiency (CUE), enabling rapid biomass accumulation and thriving under high nitrogen availability. In contrast, miners have low CUE, leading to slower biomass accumulation but supporting symbiosis in nitrogen-limited environments. Notably, miners also display self-decomposition traits that enhance nutrient recycling under scarcity. This model offers a unified framework for evaluating and understanding the interactions between ectomycorrhizal fungi and their tree hosts. (Summary by Ching Chan @ntnuchanlab) New Phytol. 10.1111/nph.70129