Traditionally microbial communities were assessed through culturing, which
limits the populations detected. Molecular techniques are becoming more popular when
assessing microbial communities. To illustrate gene variability between sites terminal
restriction fragment length polymorphism (T-RFLP) was used in this study.
Bacterial 16S rDNA and archaeal and bacterial amoA diversity was examined
from Albright Grove, Cataloochee, and Purchase Knob in Great Smoky Mountains
National Park (GSMNP) using T-RFLP. Bacterial 16S rDNA T-RFLP electoferrogram
peak data revealed that Cataloochee and Purchase Knob had a greater diversity compared
to Albright Grove, with 60 different peaks and 17 unique peaks at each site, and 60
different peaks and 18 unique peaks, respectively, while Albright Grove had a total of 45
different peaks and 9 unique peaks. A comparison showed 28.6% of major peaks were
shared between all three. Archaeal amoA T-RFLP electoferrogram peak data revealed
that Cataloochee and Purchase Knob had a greater diversity compared to Albright Grove,
with 105 different peaks and 30 unique peaks, and 103 different peaks and 22 unique
peaks at each site, respectively, while Albright Grove had a total of 82 different peaks
and 13 unique peaks at the site. No major peaks were shared between all three sites.
PCR products for bacterial amoA were only produced from Purchase Knob and generated
a total of 10 peaks.
Overall diversity appeared to be higher in the disturbed sites of Cataloochee and
Purchase Knob compared to the undisturbed site of Albright Grove. Since, the
rhizosphere is a complex system a number of other variables could impact the structure of
the microbial community, and must be taken into consideration when examining
diversity. This study has provided insight into the spatial variability of the microbial
community in the Eastern Hemlock rhizosphere, and further examination may help
mediate the devastating loss of the hemlock due to an exotic adelgid species
