Dean, S.L., Farrer, E.C., Taylor, D.L., Porras-Alfaro, A., Suding, K.N., Sinsabaugh, R.L.
NWT Accession Number: NWT1818
Nitrogen (N) deposition rates are increasing globally due to anthropogenic activities. Plant community responses to N are often attributed to altered competitive interactions between plants, but may also be a result of microbial responses to N, particularly root-associated fungi (RAF), which are known to affect plant fitness. In response to N, Deschampsia cespitosa, a codominant plant in the alpine tundra at Niwot Ridge (CO), increases in abundance, while Geum rossii, its principal competitor, declines. Importantly, G.rossii declines with N even in the absence of its competitor. We examined whether contrasting host responses to N are associated with altered plant-fungal symbioses, and whether the effects of N are distinct from effects of altered plant competition on RAF, using 454 pyrosequencing. Host RAF communities were distinct (only 9.4% of OTUs overlapped). N increased RAF diversity in G. rossii, but decreased it in D. cespitosa. D. cespitosa RAF communities were more responsive to N than G.rossii RAF communities, perhaps indicating a flexible microbial community aids host adaptation to nutrient enrichment. Effects of removing D. cespitosa were distinct from effects of N on G. rossii RAF, and D.cespitosa presence reversed RAF diversity response to N. The most dominant G. rossii RAF order, Helotiales, was the most affected by N, declining from 83% to 60% of sequences, perhaps indicating a loss of mutualists under N enrichment. These results highlight the potential importance of belowground microbial dynamics in plant responses to N deposition.
Helotiales , ITS , Endophytes , 454 pyrosequencing , Root fungi , Nitrogen deposition , Dark-septate , Species composition , Root endophytes , Mycorrhizal associations , Ectomycorrhizal fungi , Semiarid grassland , Ranunculus-adoneus , Rocky-Mountains , Atmospheric CO2 , Community
Lead PI, Investigator
Dean, S.L., Farrer, E.C., Taylor, D.L., Porras-Alfaro, A., Suding, K.N., Sinsabaugh, R.L., (2014) Nitrogen deposition alters plant-fungal relationships: linking belowground dynamics to aboveground vegetation change. Molecular Ecology 23 (6) :1364-1378 , DOI: 10.1111/mec.12541
This material is based upon work supported by the National Science Foundation under Cooperative Agreement #DEB-1637686. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necesarily reflect the views of the National Science Foundation.
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