Comparison of bacterial communities in living eastern hemlock (Tsuga canadensis) rhizospheres versus presumably dead eastern hemlock rhizospheres

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Kendall Leigh Fuller (Creator)
Institution
Western Carolina University (WCU )
Web Site: http://www.wcu.edu/404.asp
Advisor
Seán O’Connell

Abstract: The purpose of this study was to identify bacterial species associated with the rhizosphere of living and dead hemlocks (those that have been likely killed by adelgid infestation). Study of the bacterial diversity associated with the rhizosphere of hemlocks, could lead to elucidation of partnerships between bacteria and hemlocks. Samples were collected from Albright Grove, Great Smoky Mountains National Park (GSMNP), in early February 2011 from the soil attached to hemlock roots from six trees, consisting of paired live/dead trees that were found side by side. Species richness and evenness within the samples were evaluated. Variation based on time of year and over time was assessed for hemlock rhizospheres. Some of the bacteria detected in this work were unidentified at the phylum level and are likely new taxa to science. Overall, Acidobacteria was the dominant phylum making up 63% of all samples, followed by Proteobacteria at 23%, other phyla were represented at levels = 6%. Results indicated significant differences in the composition at the phylum level of Live 2011 and Dead 2011 samples. Other significant differences were found at lower levels of classification between all six comparisons of the four sample sets. This research has built upon the research of two former M.S. thesis students by using clone libraries prepared in the summer of 2006 and DNA extracts from samples collected during the winter of 2008 from the same field site. The association of microbial communities with living hemlocks is important. If hemlocks cease to exist in the GSMNP because of the infestation of the Hemlock Woolly Adelgid (HWA), then unidentified microorganisms that may be specific to hemlock may become extinct as well. If reforestation efforts were ever to take place for Eastern Hemlock in GSMNP, microbial communities associated with healthy trees could be vital in the success of this effort.

Additional Information

Publication
Thesis
Language: English
Date: 2012
Keywords
Hemlock, Microbial Ecology, Rhizosphere
Subjects
Rhizobacteria -- Great Smoky Mountains National Park (N.C. and Tenn.)
Eastern hemlock -- Microbiology -- Great Smoky Mountains National Park (N.C. and Tenn.)
Eastern hemlock -- Soils -- Great Smoky Mountains National Park (N.C. and Tenn.)
Eastern hemlock -- Great Smoky Mountains National Park (N.C. and Tenn.)
Bacteria -- Ecology -- Great Smoky Mountains National Park (N.C. and Tenn.)
Soil microbial ecology -- Great Smoky Mountains National Park (N.C. and Tenn.)
Plant-microbe relationships -- Great Smoky Mountains National Park (N.C. and Tenn.)