The Center for Adaptation Genetics and Drug Resistance at Tufts University School of Medicine. Stuart B. Levy, M.D., Director


Current and Ongoing Projects:

Pseudomonas fluorescens: Ecological Fitness Traits in Soil Bacteria - Year 22
Principal Investigator: Stuart B. Levy, M.D.
Co-PI: Mark Silby, Ph.D.


The work focuses on identifying and cloning genes for traits in soil pseudomonads, namely Pseudomonas fluorescens, which aid in their survival and competitiveness. Each gene becomes part of a library of potentially moveable traits by which to engineer bacteria for bioremediation and crop improvement. Insights provided by studies of Pseudomonas fluorescens have relevance to infectious traits in Pseudomonas aeruginosa.

Selected References

  • DeFlaun, M.F., A.S. Tanzer, A.L. Joseph, B. Marshall and S.B. Levy (1990). Development of an adhesion assay and characterization of an adhesion-deficient mutant of Pseudomonas fluorescens. Appl. Env. Microb. 56:112-119.

  • DeFlaun, M.F., B.M. Marshall, E.-P. Kulle, and S.B. Levy (1994). Tn5 insertion mutants of Pseudomonas fluorescens defective in adhesion to soil and seeds. Appl. Env. Microb. 60:2637-2642.

  • Casaz, P., A. Happel, J. Keithan, D. Read, S. Strain and S.B. Levy. (2001) The Pseudomonas fluorescens transcriptional activator AdnA is required for adhesion andmotility. Microbiology 147: 355-361.

  • Marshall, B., E. Robleto, R. Wexler, P. Casaz and S.B. Levy. (2001) The AdnA transcriptional factor affects persistence and spread of Pseudomonas fluorescens under natural field conditions. Appl. Env. Microb. 67: 852-857.

  • Robleto, E.A., I. Lopez-Hernandez, M.W. Silby and S.B. Levy. (2003) Genetic analysis of the AdnA regulon in Pseudomonas fluorescens: non-essential role of flagella in adhesion to sand and biofilm formation. J. Bacteriol. 185:453-460.

  • Silby, M.W. and S.B. Levy (2004). Use of in vivo expression technology to identify genes important in growth and survival of Pseudomonas fluorescens Pf0-1 in soil: discovery of expressed sequences with novel genetic organizations. J. Bacteriol. 186: 7411-4719

  • Silby, M.W., P.B. Rainey, & S.B. Levy (2004) IVET experiments in Pseudomonas fluorescens reveal cryptic promoters at loci associated with recognizable overlapping genes. Microbiology. 150:518-520

  • Silby, M.W. and S.B. Levy. (2008). Overlapping protein-encoding genes in Pseudomonas fluorescens Pf0-1. PLoS genetics 4(6):e1000094.

  • Silby, M.W., J.S. Nicoll & S.B. Levy. (2009). Requirement of Polyphosphate by Pseudomonas fluorescens Pf0-1 for competitive fitness and heat tolerance in laboratory media and sterile soil. Appl. Environ. Microbiol. 75: 3872-81.

  • Kim, W., M.W. Silby, S.O. Purvine, J.S. Nicoll, K.K. Hixson, M.Monroe, C.D. Nicora, M.S. Lipton, and S.B. Levy. (2009). Proteomic Detection of Non-Annotated Protein-Coding Genes in Pseudomonas fluorescens Pf0-1. PLoS One 4(12):e8455

  • Silby, M. and S.B. Levy. Overlapping protein-encoding genes in Pseudomonas fluorescens Pf0-1 PlosGenet (2008) 4(6): e 1000094

  • Silby, M. W., Nicoll, J. S., and Levy, S. B. (2009) Requirement of polyphosphate by Pseudomonas fluorescens Pf0-1 for competitive fitness and heat tolerance in laboratory media and sterile soil. App. Environ. Microbiol.75:3872-3881.

  • Kim, O.K., L. K. Garrity-Ryan, V. J. Bartlett, M. C. Grier, A. K. Verma, G. Medjanis, J. E. Donatelli, A. B. Macone, S. K. Tanaka, S. B. Levy, and M. N. Alekshun. (2009) N-Hydroxybenzimidazole Inhibitors of the transcription factor LcrF in Yersinia: novel antivirulence agents. J. Med. Chem. 52: 5626-5636

  • Silby, M. W., et al. (2009). Genomic and functional analyses of diversity and plant interactions of Pseudomonas fluorescens. Genome Biology10(5):R51

External Site

Please be sure to visit Pseudomonasfluorescens.org.

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