American chestnut (Castanea dentata) trees are rare in northeastern American forests due to the pathogen Cryphonectria parasitica. But C. dentata could return and become a dominate canopy species with sizeable ecological implications. Most trees, including C. dentata, form mutualistic relationships with various mycorrhizal fungal species. Our objectives were to assess the mycorrhizal fungi shared by C. dentata and other co-occurring tree species when planted together, and to observe how these shared fungal communities change over time. These results may provide clues about C. dentata’s chances of future success. To investigate, we created a greenhouse soil-feedback experiment with tree-saplings, pairing C. dentata with one of three common central-hardwood forest species: Acer rubrum, Quercus rubra, Pinus resinosa. Solo-planted trees served as controls. Saplings were planted with a 1:1 mixture of sand and forest soils collected from underneath corresponding species of mature trees at Louis Calder Center in Armonk, NY in June 2017. Soil cores were collected in late June 2017 and in November 2017. This collection scheme was designed to enable fungal interaction and to allow us to observe possible impacts of seasonality. Soil samples were sequenced for fungi via Illumnia MiSeq (using primers ITS1F-ITS4) and were analyzed in QIIME and FUNGuild.
Results/Conclusions
Due to high mortality of our Q. rubra controls and treatments, we removed the species from this experiment. Preliminary results suggest a more diverse mycorrhizal fungal composition and abundance in our treatments versus in our controls which may be the result of interspecific competition. Data also suggest a difference in mycorrhizal composition between our spring and late-fall samples, which tells us seasonality plays a role in mycorrhizal community structure in our system. Growth did not clearly differ (p > 0.05) between saplings grown in competition with other saplings and those grown alone. These results are consistent with those from similar studies. Future research will further explore fungal communities of northeastern tree species.