Incorporating microbes into plant community ecology
Walker, John F , Jumpponen, Ari .
Seasonal Dynamics of Mycorrhizal Fungus Communities.
Communities of rhizosphere-associated fungi are diverse and variable temporally and spatially. Fungi that form ectomycorrhizal symbioses are particularly diverse across small spatial scales, with communities typically comprised of few abundant core taxa and numerous rare species. Elucidating the degree to which intra-annual temporal variation in these communities affects diversity and functionality would allow important inferences about partitioning of fungal symbionts across the season, transitions between functional guilds of fungi, and host plant plasticity at the soil interface. We present results from three recent studies focusing on temporal dynamics of root-associated fungi. First, a comparison among ectomycorrhizal associates of red oak seedlings in a temperate eastern forest retrieved from mid-summer and early fall suggested that richness of certain ectomycorrhizal fungus groups changes over the season. Second, an investigation of fungal diversity on roots of Quercus spp. in non-forested rural and urban sites in the Flint Hills region (KS, USA) indicated a transition from putative root-associated antagonists and saprobes that were abundant early in the growing season to common ectomycorrhizal fungi later. Changes in the richness of ectomycorrhizal groups were again observed, although the specific pattern was not consistent with the previous study. Third,an investigation of changes in fungal communities associated with a dominant C4 prairie grass (Andropogon gerardii) forming arbuscular mycorrhizal symbioses indicated a similar transition from pathogenic/saprobic fungi in the spring to dominance by mycorrhizal associates later in the growing season. Drivers for these shifts in fungal communities and their functional consequences remain unclear. However, root turnover in the spring may be a primary factor combined secondarily with differences in environmental tolerances and niche preferences of the fungi. Determining whether the observed seasonal shifts in broad functional groups are universal and whether patterns of seasonal partitioning in mycorrhizal groups are biome- or ecosystem-specific are valuable future research directions.
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1 - Appalachian State University, Biology, 572 Rivers St, Boone, NC, 28608, USA
2 - Kansas State University, Division of Biology, 116 Ackert Hall, Manhattan, KS, 66506, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Westminster Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 10:15 AM