Nitrogen deposition alters plant-fungal relationships: linking belowground dynamics to aboveground vegetation change

• Published in: Molecular Ecology
• Main Authors: D. Lee Taylor, Emily C. Farrer, Katharine N. Suding, Sarah L. Dean, Andrea Porras-Alfaro, Robert L. Sinsabaugh
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley 2013
• Subjects: Genetics; Ecology; Evolution; Behavior and Systematics; envir; socio; Tundra
• Online Access: https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmec.12541; http://onlinelibrary.wiley.com/wol1/doi/10.1111/mec.12541/fullpdf; https://doi.org/10.1111/mec.12541; https://www.onlinelibrary.wiley.com/doi/full/10.1111/mec.12541; http://www.ncbi.nlm.nih.gov/pubmed/24112704; https://academic.microsoft.com/#/detail/2130609602

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.