Tree genotype influences ectomycorrhizal fungal community structure: Ecological and evolutionary implications

Although the eco-evolutionary dynamics of multicellular organisms are intertwined with the microorganisms that colonize them, there is only a rudimentary understanding of how a host's genotype influences its microbiome. We utilize Populus angustifolia to test whether communities of essential symbionts, ectomycorrhizal fungi (EMF), vary among host genotypes. Further, we test whether EMF communities covary among tree genotypes with the chemistry of senescent leaves and aboveground biomass, traits important to tree fitness, and carbon and nutrient cycling. We found: 1) EMF composition, colonization and the Basidiomycota to Ascomycota ratio varied among tree genotypes (broad-sense heritability = 0.10–0.25). 2) EMF composition did not covary among genotypes with aboveground biomass but it did covary with senescent leaf chemistry (rho = 0.29), primarily due to a single genotype. These findings demonstrate a link between tree genotype and EMF communities, which has implications for fungal diversity, host-symbiont interactions and aboveground-belowground linkages in ecological and evolutionary contexts.