Center for Microbial Ecology

Research Program

Community Analysis Thrust Group

Contributors:

STC Faculty -- K. Gross, M. Klug, E. Paul, T. Schmidt, F. de Bruijn, C. Criddle, R. Hickey, F. Dazzo, A. Jain, P. Robertson, J. McGrath, R. Hollingsworth, J. Tiedje

Collaborators -- T. Hattori (Tohuku Univ.), J. Lawton, A. Hector (Imperial College, England), J. Zhou (ORNL), R. O'Neill (ORNL), R. Fulthorpe (Univ. of Toronto), J. Rademaker (Dutch Culture Collection), C. Moyer (Western Washington Univ.), D. Gilichinsky (Russian Academy of Sciences), Beicheng Xia (Zhongshan Univ.)

Postdocs -- W. Goodfriend, S. Hashsham, A. Fernandez, K. Nusslein, J.C. Cho, A. Murray, S. Nold, S. Dedysh, T. Vishnivetskaya, O. Kotsiourbenko

Graduate Students -- L. Broughton, D. Buckley, S. Seston, C. Wright, C. Blackwood, G. Braker, L. Dethlefsen, S. Asuming-Brempong

1999 Research Accomplishments:

1. Local Scale Patterns of Microbial Diversity

1. Linking diversity in plant communities to soil microbial communities and processes.
2. Species vs. diversity effects on microbial communities and processes.
3. Bacterial communities of physical soil fractions.
4. Effect of disturbance (agronomic treatment) and plant community composition on microbial community structure as measured by quantifying 16S rRNA.
5. Effects of plant residue quality on microbial community structure.

2. Functional Stability and Community Structure Relationships in Bioreactor Communities

1. Cause and effects of shifts in bioreactor community composition.
2. Linking community structure with function.

Future Plans:

We plan to follow up and expand the plant-soil field work comparing patterns of microbial communities across fields with a series of greenhouse and field experiments to determine the relative importance of "plant" vs. "soil" effects on soil microbial community structure. The greenhouse experiments will use soil from six different successional fields ranging from 10 to 50 years and varying in soil fertility and plant community composition. The effects of soil fertility, time since abandonment, and plant functional group (C3 and C4 grasses, legumes, non-legumous dicots) on the soil microbial community will be evaluated using BIOLOG, whole community PLFA, FAME on isolates, and tRFLP's. In addition, monocultures and mixtures of the same plant species used in the greenhouse will be established in the fields (from which soil was taken for the greenhouse experiments) to determine if the results of the greenhouse experiments hold true in a more realistic environment.

Funding for work under this thrust has been partially covered by new grants from DOE, EPA and two grants from NSF. Some of the community analysis work will be more directly focused on the bioremediation systems since the current stage of that work requires community analyses. We are also proposing to the State/University an infrastructure effort to advance DNA microarray technology for community studies. These approaches could revolutionize what can be learned about ecological interactions. We are calling this new theme "ecological genomics". Within the last month we have carried out successful experiments with DNA microarrays with two different biological systems and addressing different types of questions. Hence, we have mastered this technology and can now use it to address a variety of mechanistic hypotheses.