Journal of Bacteriology, November 2007, p. 8154-8164, Vol. 189, No. 22
0021-9193/07/$08.00+0 doi:10.1128/JB.00585-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
SadC Reciprocally Influences Biofilm Formation and Swarming Motility via Modulation of Exopolysaccharide Production and Flagellar Function
Judith H. Merritt,
Kimberly M. Brothers,
Sherry L. Kuchma, and
George A. O'Toole*
Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755
Received 16 April 2007/
Accepted 11 June 2007
Pseudomonas aeruginosa has served as an important organism in the study of biofilm formation; however, we still lack an understanding of the mechanisms by which this microbe transitions to a surface lifestyle. A recent study of the early stages of biofilm formation implicated the control of flagellar reversals and production of an exopolysaccharide (EPS) as factors in the establishment of a stable association with the substratum and swarming motility. Here we present evidence that SadC (PA4332), an inner membrane-localized diguanylate cyclase, plays a role in controlling these cellular functions. Deletion of the sadC gene results in a strain that is defective in biofilm formation and a hyperswarmer, while multicopy expression of this gene promotes sessility. A
sadC mutant was additionally found to be deficient in EPS production and display altered reversal behavior while swimming in high-viscosity medium, two behaviors proposed to influence biofilm formation and swarming motility. Epistasis analysis suggests that the sadC gene is part of a genetic pathway that allows for the concomitant regulation of these aspects of P. aeruginosa surface behavior. We propose that SadC and the phosphodiesterase BifA (S. L. Kuchma et al., J. Bacteriol. 189:8165-8178, 2007), via modulating levels of the signaling molecule cyclic-di-GMP, coregulate swarming motility and biofilm formation as P. aeruginosa transitions from a planktonic to a surface-associated lifestyle.
* Corresponding author. Mailing address: Department of Microbiology and Immunology, Rm. 505, Vail Building, Dartmouth Medical School, Hanover, NH 03755. Phone: (603) 650-1248. Fax: (603) 650-1245. E-mail: georgeo{at}dartmouth.edu
Published ahead of print on 22 June 2007.
Journal of Bacteriology, November 2007, p. 8154-8164, Vol. 189, No. 22
0021-9193/07/$08.00+0 doi:10.1128/JB.00585-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Murray, T. S., Kazmierczak, B. I.
(2008). Pseudomonas aeruginosa Exhibits Sliding Motility in the Absence of Type IV Pili and Flagella. J. Bacteriol.
190: 2700-2708
[Abstract]
[Full Text]
-
Maddula, V. S. R. K., Pierson, E. A., Pierson, L. S. III
(2008). Altering the Ratio of Phenazines in Pseudomonas chlororaphis (aureofaciens) Strain 30-84: Effects on Biofilm Formation and Pathogen Inhibition. J. Bacteriol.
190: 2759-2766
[Abstract]
[Full Text]
-
Ferreira, R. B. R., Antunes, L. C. M., Greenberg, E. P., McCarter, L. L.
(2008). Vibrio parahaemolyticus ScrC Modulates Cyclic Dimeric GMP Regulation of Gene Expression Relevant to Growth on Surfaces. J. Bacteriol.
190: 851-860
[Abstract]
[Full Text]
-
Yildiz, F. H.
(2008). Cyclic Dimeric GMP Signaling and Regulation of Surface-Associated Developmental Programs. J. Bacteriol.
190: 781-783
[Full Text]
-
Wolfe, A. J., Visick, K. L.
(2008). Get the Message Out: Cyclic-Di-GMP Regulates Multiple Levels of Flagellum-Based Motility. J. Bacteriol.
190: 463-475
[Full Text]
-
Kuchma, S. L., Brothers, K. M., Merritt, J. H., Liberati, N. T., Ausubel, F. M., O'Toole, G. A.
(2007). BifA, a Cyclic-Di-GMP Phosphodiesterase, Inversely Regulates Biofilm Formation and Swarming Motility by Pseudomonas aeruginosa PA14. J. Bacteriol.
189: 8165-8178
[Abstract]
[Full Text]
Copyright © 2007 by the American Society for Microbiology. All rights reserved.