Using stable-isotope vibrational microspectroscopy to reveal hyphal scale interactions and competition between ectomycorrhizal and saprotrophic fungi

Interguild fungal interactions and competition for resources in soils significantly affect overall functioning and productivity of fungal community and, in turn, soil biogeochemical cycles and fluxes of respired CO2. According to macroscale observations, the fluxes can be suppressed or exacerbated, which means that interacting fungi can contribute to or help sequester anthropogenic CO2 emissions.

Better understanding of currently understudied fundamental mechanisms behind fungal interactions can make sure that our soil management practices promote the latter. The purpose of this project is to develop state-of-the-art stable-isotope vibrational microspectroscopy based approach for in vivo monitoring of hyphal metabolic processes among competing ectomycorrhizal and saprotrophic fungi, and to identify nutrient (C and N) conditions which determine ‘the winner’ of the competition and its influence on organic matter decomposition. For this, I will first measure the hyphal growth and metabolic activity rates in single fungal strains growing in soil chips by quantifying cellular incorporation of stable-isotope labeled nutrient substrates via analyzing characteristic spectral signatures obtained through vibrational microspectroscopy. I will then evaluate how interguild interactions and competition affect these rates and substrate decomposition under different nutrient conditions. Finally, I will determine if loss of nutrients to the opposing fungus takes place among the competitors.