Linking ecology and evolution: a genomic and bioinformatics analysis of fungal traits in plant-associated fungi

The fungal kingdom is a primary driver of nutrient cycling in terrestrial ecosystems. While historically categorised into rigid ecological guilds such as saprotrophs, pathogens, and mutualists, recent genetic evidence suggests that Ectomycorrhizal (EcM) fungi have retained a vast repertoire of carbon-degrading and nutrient-acquisition genes from their saprotrophic ancestors, challenging the nutritional boundaries of these guilds. This thesis uses a genomic trait-based approach to investigate the functional assembly of EcM communities in temperate forest ecosystems, specifically under broadleaved tree species. I analysed fungal communities in a common garden experiment plots in Denmark dominated by Fagus sylvatica, Tilia cordata, and Picea abies. However, due to low genomic coverage in coniferous plots, correlation analyses focused on the broadleaved species. I focused on the interface between the organic horizon and the mineral soil and integrated existing fungal community data with genomic reference data to calculate the Community Weighted Mean (CWM) of key functional genes. With this, I tested the hypothesis that soil chemical properties and fertility gradients act as environmental filters for EcM communities. By linking soil environmental filters to genomic traits, this thesis contributes to a broader understanding of how fungal communities adapt to and shape the terrestrial environment.