Dr. Kim Cowles

Although bacterial human pathogens, such as Salmonella enterica, are usually studied in the context of their animal hosts, it has become increasingly apparent that a significant portion of their life cycle occurs on plants. This adaptation to the plant environment has led to increased incidence of human disease, particularly in the context of fresh produce. The fundamental biology of Salmonella in the plant environment remains vastly ill-defined and little is known about the fitness factors required for resource competition and survival. Her project focuses on the role of the secondary messenger cyclic di-GMP in Salmonellacolonization of plant tissues. In many bacteria, c-di-GMP regulates motility, biofilm formation, and virulence. To date, we have found that five of the twelve putative diguanylate cyclases (involved in the production of c-di-GMP) are involved in colonization of alfalfa roots or survival on tomato leaves. Interestingly, our data demonstrate that some of these factors are important in both environments while others are needed in only one, indicating that environmental cues may influence the regulation of c-di-GMP production.

Education and Research Experience

Postdoctoral Fellow, Department of Molecular Biology, Princeton University, Princeton, NJ, 2006-2011 (NIAID Ruth L. Kirschstein National Research Service Award, 2008-2011)
Ph.D., Microbiology, University of Wisconsin-Madison, 2006
B.S., Microbiology, University of Illinois-Urbana-Champaign, 2000 (summa cum laude)


Cowles, KN, Willis, DK, Engle, TN, Jones, JB, and Barak, JD. 2016. Diguanylate cyclases, AdrA and STM1987, regulate Salmonella enterica exopolysaccharide production during plant colonization in an environment-dependent manner. Appl. Environ. Microbiol. 82(4): 1237-1248. Link

Merritt, JH, Ha, DG, Cowles, KN, Lu, W, Morales, DK, Rabinowitz, J, Gitai, Z, and O’Toole, GA. 2010 Specific control of Pseudomonas aeruginosa surface-associated behaviors by two c-di-GMP diguanylate cyclases. MBio. 19:1(4). Pii e00183-10. Link

Cowles, KN and Gitai, Z. 2010 Surface association and the MreB cytoskeleton regulate pilus production, localization and function in Pseudomonas aeruginosa. Mol Microbiol. 76(6):1411-26. Link

Herbert, EE, Cowles, KN, and Goodrich-Blair, H. 2007 CpxRA regulates mutualism and pathogenesis in Xenorhabdus nematophila. Appl Environ Microbiol. 73(24):7826-36. Link

Cowles KN, Cowles CE, Richards GR, Martens EC, Goodrich-Blair H. 2007 The global regulator Lrp contributes to mutualism, pathogenesis and phenotypic variation in the bacterium Xenorhabdus nematophila. Cell Microbiol. 9(5):1311-23. Link

Park Y, Herbert EE, Cowles CE, Cowles KN, Menard ML, Orchard SS, Goodrich-Blair H. 2007 Clonal variation in Xenorhabdus nematophila virulence and suppression of Manduca sexta immunity. Cell Microbiol. 9(3):645-56. Link

Cowles KN, Goodrich-Blair H. 2005 Expression and activity of a Xenorhabdus nematophila haemolysin required for full virulence towards Manduca sexta insects. Cell Microbiol. 7(2):209-19. Link