Sustainable Agricultural Systems Laboratory : People & Places

Summary of Research

Dr. Buyer is the Lead Scientist on the Soil Microbiology Project. Three main objectives are to: (1) develop improved methods to characterize soil microbial communities, (2) analyze the factors controlling soil microbial community structure and function, and (3) develop strategies to improve colonization of root and seed by beneficial microorganisms. We are currently working on improving methodology for the identification of bacteria by analysis of fatty acid methyl esters. We are also developing a method for analysis of soil DNA by T-RFLP using paramagnetic beads which we believe will be faster and cheaper than current T-RFLP methods. Interactions between soil, root, seed, and microbial communities are being studied in growth chamber experiments, using fatty acid analysis, substrate utilization assays, and analysis of soil DNA. The effects of conventional and sustainable agricultural management systems on soil microbial communities are being studied in Maryland. Field studies in arid rangelands are being conducted to determine the effects of grazing intensity on soil microbial communities. We are researching the non-target effects of genetically engineered Bt corn on soil and rhizosphere microbial communities in growth chamber and field experiments. The role of small molecules such as carbohydrates, amino acids, and organic acids in colonization, growth, and metabolism of beneficial microorganisms is being studied by analysis of seed and root exudates using gas chromatography and mass spectroscopy.

Buyer, J.S., D.P. Roberts, and E. Russek-Cohen. 1999. Microbial community structure and function in the spermosphere as affected by soil and seed type. Can. J. Microbiol. 45:138-144.

Roberts, D.P., P.D. Dery, I. Yucel, J.S. Buyer, M.A. Holtman, and D.Y. Kobayashi. 1999. Role of pfkA and general carbohydrate catabolism in seed colonization by Enterobacter Cloacae. Appl. Environ. Microbiol. 65:2513-2519.

Roberts, D.P., E.L. Stromberg, G.H. Lacy, and J.S. Buyer. 1999. Biological Disease Control: Considerations for Seed Treatment and Stand Establishment. Acta Horticulturae 504:69-74.

Stromberg, E.L., D.P. Roberts, G.H. Lacy, P.D. Dery, and J.S. Buyer. 1999. Field evaluation of selected bacterial isolates and seed treatment fungicides for the control of take-all in Jackson soft red winter wheat, 1998. Bio. Cult. Tests Control Plant Dis. 14:127-129.

Moline, H., J.E. Hubbard, J.S. Karns, J.S. Buyer, and J.D. Cohen. 1999. Selective isolation of bacterial antagonists of Botrytis cinerea. Eur. J. Plant Path. 105:95-101.

Roberts, D.P., P.D. Dery, I. Yucel, and J.S. Buyer. 2000. Importance of pfkA for rapid growth of Enterobacter cloacae during colonization of crop seeds. Appl. Environ. Microbiol. 66:87-91.

Stromberg, E.L., D.P. Roberts, G.H. Lacy, P.D. Dery, and J.S. Buyer. 2000. Field evaluation of selected bacterial isolates and seed treatment fungicides for the control of Take-all in Jackson Soft Red Winter wheat, 1999. Bio. Cult. Tests Control Plant Dis. 15:135-139.

Li, W., D.P. Roberts, P.D. Dery, N.M. Mock, C.J. Baker, and J.S. Buyer. 2000. Effect of decreased catabolic capability of Enterobacter cloacae strain A-11 on root colonization and suppression of damping-off caused by Pythium ultimum on cucumber. Proceedings of the 5th International PGPR Workshop, Cordoba, Argentina. http://www.ag.auburn.edu/argentina. (Symposium Paper)

Gagliardi, J.V., J.S. Buyer, J.S. Angle, and E. Russek-Cohen. 2001. Structural and functional analysis of whole-soil microbial communities for risk and efficacy testing following microbial inoculation of wheat roots in diverse soils. Soil Biol. Biochem. 33:25-40.

Stromberg, E.L., D.P. Roberts, G.H. Lacy, P.D. Dery, and J.S. Buyer. 2001. Field evaluation of selected bacterial isolates and seed treatment fungicides for the control of Take-all in Madison Soft Red Winter Wheat, 2000. Bio. Cult. Tests Control Plant Dis. Report 2001:S25.

Buyer, J.S., D.P. Roberts, P. Millner, and E. Russek-Cohen. 2001. Analysis of fungal communities by sole carbon source utilization profiles. J. Microbiol. Methods 45:53-60.

Royt, P.W., R.V. Honeychuck, V. Ravich, P. Ponnaluri, L.K. Pannell, J.S. Buyer, V. Chandhoke, W. Stalick, L.C. de Sesso, and R. Ghei. 2001. Pseudan: A novel iron chelator isolated from the cytoplasmic membrane of Pseudomonas aeruginosa. Bioorganic Chemistry 29:387-397

Mummey, D.L., P.D. Stahl, and J.S. Buyer. 2002. Soil microbiological and physicochemical properties 20 years after surface mine reclamation. Soil Biol. Biochem. 34:1717-1725

Mummey, D.L., P.D. Stahl, and J.S. Buyer. 2002. Microbial biomarkers as an indicator of ecosystem recovery following surface mine reclamation. Applied Soil Ecology 21:251-259

Buyer, J.S. 2002. Rapid sample processing and fast chromatography for identification of bacteria by fatty acid analysis. J. Microbiol. Methods 51:209-215

Buyer, J.S., D.P. Roberts, and E. Russek-Cohen. 2002. The rhizosphere effect and microbial community structure. Can. J. Microbiol. 48:955-964.

Stromberg, E.L., D.P. Roberts, G.H. Lacy, S.M. Lohrke, W. Li, and J.S. Buyer. 2002. Field evaluation of selected bacterial isolates and seed treatment fungicides for the control of take-all in Roanoke soft red winter wheat in Virginia, 2001. Biol. Cult. Tests Control Plant Dis. 17:S08.

Buyer, J.S. 2002. Identification of bacteria from single colonies by fatty acid analysis. J. Microbiol. Methods 48:259-265.

Buyer, J.S. 2003. Improved fast gas chromatography for FAME analysis of bacteria. J. Microbiol. Methods. In press.