More than serendipity: the potential to manage soil carbon and emissions while promoting low-input agriculture with serendipitoid mycorrhizae

Organic matter (OM) has a tremendous influence on the biological, chemical, and physical properties of soils, making it a vital component of healthy agricultural systems. Release of the nutrients locked within soil OM requires the activity of soil microorganisms, primarily decomposers, to transform it into nutritive forms that can be used by other microbes and plants. OM turnover is a good thing, as it liberates the locked up nutrients. However, when this liberation is accomplished by free-living decomposer communities, i.e., those not typically forming relationships with plants, the carbon may be used mostly to form microbial biomass and the rest respired as CO₂, thereby aggravating greenhouse gas emission. Serendipitoid fungi (e.g., Serendipita spp.) are soil-dwelling basidiomycetes, known for decades to form mycorrhizal associations with wide variety of plant species. We hypothesize that serendipitoid fungi are capable of decomposing OM in a manner akin to free-living decomposer communities. However, serendipitoid fungi are capable of colonizing the root systems of plant community members, potentially restricting access to nutritional stores in the soil, thus imparting efficiency to the system and limiting unnecessary losses. From our perspective, this is a more rational, resilient, and ultimately more sustainable strategy than the annual addition of inorganic forms of micro- and macronutrients. Using microbes like Serendipita spp. in this manner could ultimately make the system less susceptible to nutritional fluxes that may influence productivity and stress tolerance in our crop plants.