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Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Burke, David [1], Carrino-Kyker, Sarah [1], Kluber, Laurel [1], Petersen, Sheryl [2], Coyle, Kaitlin [3], DeForest, Jared [4], Smemo, Kurt [5], Hewins, Charlotte [1].

Effects of soil pH and P availability on root associated fungal communities in a temperate hardwood forest.

Many temperate hardwood forests in the Northeastern US are affected by chronic acid deposition, which can lower soil pH and limit the availability of nutrients such as phosphorus (P). However, previous work found a lack of response of forest trees to changes in pH and P availability, suggesting that forest trees possess some mechanism for overcoming nutrient limitations associated with acidified conditions. One important mechanism for overcoming pH-induced P limitation may be through increased mycorrhizal colonization and alterations in mycorrhizal community structure. To examine this question, we began an ecosystem-level pH and P manipulation in the fall of 2009, which increased pH by more than 1.5 units and/or increased P availability in 72 experimental plots in northern and southern Ohio. Two years after treatment initiation, we sampled roots of hardwood trees to examine effects of changes in soil chemistry on ectomycorrhizal colonization and community structure using tag-encoded 454 pyro-sequencing of the internal transcribed spacer (ITS) region of the rDNA. We saw no significant differences in the number of ECM tips with treatment, although root colonization was higher in treatment plots from northern Ohio. Our 454 pyro-sequencing efforts yielded over 100,000 sequences from the treatment plots, of which 72,000 met quality control criteria and were used for community analysis. Using a 97% similarity cutoff to distinguish between operational taxonomic units (OTUs), we were able to detect 2961 OTUs from root tips colonized by ectomycorrhizal fungi. These OTUs were placed into 183 different genera and used for non-metric multidimensional scaling (NMS) and PERMANOVA procedures. We found significant differences (P = 0.04) in fungal communities between northern and southern Ohio treatment plots, as well as significant differences (P < 0.01) between fungal communities in elevated pH versus non-elevated pH plots, with some genera (e.g. Sebacinaceae and Thelephoraceae) being significant indicators of elevated pH plots. Although P addition had no treatment effect on fungal communities in general, fungal community patterns were significantly correlated with soil pH, acidity, and bioavailable forms of P. Our results indicate that changes in soil pH and P availability can have significant effects on fungal communities in northern hardwood forests and future work will examine the functional consequences of these changes for nutrient cycling and tree growth.

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1 - The Holden Arboretum, 9500 Sperry Road, Kirtland, OH, 44094, USA
2 - Case Western Reserve University, Department of Biology, Cleveland, OH, USA
3 - North Carolina State University , Department of Genetics, Raleigh, NC, USA
4 - Ohio University , Department of Environmental and Plant Biology, Athens, OH, USA
5 - The Holden Arboretum, 9500 Sperry Road, Kirtland, OH, USA

Acid rain

Presentation Type: Oral Paper:Papers for Topics
Session: 8
Location: Prince of Wales/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 8:15 AM
Number: 8002
Abstract ID:263
Candidate for Awards:None

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