Multiplicity of Fungal Form and Function in Arctic-Alpine Ecosystems
Fujimura, Kei E. , Egger, Keith N. .
Effects of experimental warming on root-associated fungal communities in arctic tundra.
We report on culture-independent and culture-dependent experiments to examine the effects of experimental warming on root-associated fungal communities in high arctic tundra at Alexandra Fiord, Nunavut, Canada. Open-topped chambers were placed over vegetation to simulate the effects of climate warming. For the culture-independent study, root-associated fungal communities inhabiting Salix arctica in experimentally-warmed and ambient plots were assessed using terminal restriction fragment length polymorphism (T-RFLP) analysis of nuclear-encoded ribosomal RNA genes (rDNA). Lower genotype frequency and richness were found on a site with dolomitic soils compared to sites with granitic soils. Genotype frequency tended to be higher in warmed compared to ambient plots for all sites, but site characteristics (e.g. pH, soil parent materials) were the primary factors structuring the fungal community. We also found an increase in the density of fungal genotypes on roots, possibly associated with increased C allocation belowground. For the culture-dependent study, we isolated fungi from Dryas integrifolia, Salix arctica, Cassiope tetragona, and Saxifraga oppositifolia from the same plots. DNA was extracted from cultures, and portions of the nuclear rDNA were amplified and digested with restriction endonucleases. Cluster analysis of RFLP patterns was used to screen samples for DNA sequencing, and representative rDNA sequences were used to infer phylogenetic affinities. Sequence analysis showed that culturable root-associated fungi were mostly Ascomycota that fell into several groups: mycorrhizal fungi with affinities to Rhizoscyphus ericae; dark septate endophytes; putative root pathogens with affinities to the Dothideomycetes; and a variety of other fungi showing affinities to members of the Helotiales.
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1 - University of Northern British Columbia, Ecosystem Science & Management Program, Prince George, BC, V2N 4Z9, Canada
dark septate endophytes
Presentation Type: Symposium or Colloquium Presentation
Location: Ballroom 3/Cliff Lodge - Level B
Date: Tuesday, July 28th, 2009
Time: 9:15 AM