Record ID No. |
1799 |
Author(s) |
Walker, J.F., Miller, O.K., Horton, J.L , 2008 |
Affiliation |
Appalachian State University, Department of Biology, 572 Rivers St, Boone,NC 28608 USA |
Title |
Seasonal dynamics of ectomycorrhizal fungus assemblages on oak seedlings in the southeastern Appalachian Mountains |
Source. Vol.(no):Page |
Mycorrhiza.18(3):123-132p. |
Categories |
Ectomycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Organism |
n.a. |
Country |
United States |
Abstracts |
The potential for seasonal dynamics in ectomycorrhizal (EM) fungal assemblages
has important implications for the ecology of both the host trees and the fungal associates. We
compared EM fungus distributions on root systems of out-planted oak seedlings at two sites in
mixed southeastern Appalachian Mountain forests at the Coweeta Hydrologic Laboratory in North
Carolina, from samples taken in mid-July and early September. Species level EM fungus type
specificity, and identification in some cases, was enabled by direct sequencing of the mycobionts
from the seedling roots. Seventy-four EM fungal ITS types were documented, most of which occurred
only in the midsummer or early-fall samples, respectively. Cenococcum geophilum (morphotyped) was
ubiquitously present and accounted for the majority of root tips sampled. Abundance and relative
frequency of types other than C. Geophilum were significantly higher in the July samples, while
C. Geophilum was significantly more frequent and abundant in September. Several generalistic
dominants were found fairly equally at both sites and on both sample dates. Other taxa with
relatively high frequency were recovered from both sites and tree seedling species, but were
reliable indicators occurring primarily in the July sample (e.g., Laccaria cf laccata). Notable
shifts in mycobiont dominance were apparent in relation to sample date, including increases in
Cortinarius spp. Richness, decreases in Thelephoraceae richness, and the disappearance of Amanita
spp. Types in the early fall compared to midsummer samples. However, diversity and rarity were
high and differences in overall community composition (other than C. Geophilum) by season were
not significant based on multi-response permutation procedures. Although these results based on a
single growing season are preliminary, changes in abundance and frequency, detection of
significant indicator species, and the apparent systematic affinities of shifting EM types
support the potential for seasonal variability in EM associations in this system.
|