Previous Article | Next Article 
Journal of Bacteriology, October 2007, p. 7077-7088, Vol. 189, No. 19
0021-9193/07/$08.00+0 doi:10.1128/JB.00906-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
The ExpR/Sin Quorum-Sensing System Controls Succinoglycan Production in Sinorhizobium meliloti
Sarah A. Glenn,
Nataliya Gurich,
Morgan A. Feeney,
and
Juan E. González*
Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas 75083-0688
Received 8 June 2007/
Accepted 16 July 2007
Sinorhizobium meliloti is a gram-negative soil bacterium capable of forming a symbiotic nitrogen-fixing relationship with its plant host, Medicago sativa. Various bacterially produced factors are essential for successful nodulation. For example, at least one of two exopolysaccharides produced by S. meliloti (succinoglycan or EPS II) is required for nodule invasion. Both of these polymers are produced in high- and low-molecular-weight (HMW and LMW, respectively) fractions; however, only the LMW forms of either succinoglycan or EPS II are active in nodule invasion. The production of LMW succinoglycan can be generated by direct synthesis or through the depolymerization of HMW products by the action of two specific endoglycanases, ExsH and ExoK. Here, we show that the ExpR/Sin quorum-sensing system in S. meliloti is involved in the regulation of genes responsible for succinoglycan biosynthesis as well as in the production of LMW succinoglycan. Therefore, quorum sensing, which has been shown to regulate the production of EPS II, also plays an important role in succinoglycan biosynthesis.
* Corresponding author. Mailing Address: Department of Molecular and Cell Biology, University of Texas at Dallas, RL 11, Richardson, TX 75083-0688. Phone: (972) 883-2526. Fax: (630) 604-3093. E-mail:
jgonzal{at}utdallas.edu
Published ahead of print on 20 July 2007.
Present address: Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115.
Journal of Bacteriology, October 2007, p. 7077-7088, Vol. 189, No. 19
0021-9193/07/$08.00+0 doi:10.1128/JB.00906-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Rinaudi, L. V., Gonzalez, J. E.
(2009). The Low-Molecular-Weight Fraction of Exopolysaccharide II from Sinorhizobium meliloti Is a Crucial Determinant of Biofilm Formation. J. Bacteriol.
191: 7216-7224
[Abstract]
[Full Text]
-
Morris, J., Gonzalez, J. E.
(2009). The Novel Genes emmABC Are Associated with Exopolysaccharide Production, Motility, Stress Adaptation, and Symbiosis in Sinorhizobium meliloti. J. Bacteriol.
191: 5890-5900
[Abstract]
[Full Text]
-
Gurich, N., Gonzalez, J. E.
(2009). Role of Quorum Sensing in Sinorhizobium meliloti-Alfalfa Symbiosis. J. Bacteriol.
191: 4372-4382
[Abstract]
[Full Text]
-
Edwards, A., Frederix, M., Wisniewski-Dye, F., Jones, J., Zorreguieta, A., Downie, J. A.
(2009). The cin and rai Quorum-Sensing Regulatory Systems in Rhizobium leguminosarum Are Coordinated by ExpR and CinS, a Small Regulatory Protein Coexpressed with CinI. J. Bacteriol.
191: 3059-3067
[Abstract]
[Full Text]
-
Subramoni, S., Venturi, V.
(2009). LuxR-family 'solos': bachelor sensors/regulators of signalling molecules. Microbiology
155: 1377-1385
[Abstract]
[Full Text]
-
Patankar, A. V., Gonzalez, J. E.
(2009). An Orphan LuxR Homolog of Sinorhizobium meliloti Affects Stress Adaptation and Competition for Nodulation. Appl. Environ. Microbiol.
75: 946-955
[Abstract]
[Full Text]
-
McIntosh, M., Krol, E., Becker, A.
(2008). Competitive and Cooperative Effects in Quorum-Sensing-Regulated Galactoglucan Biosynthesis in Sinorhizobium meliloti. J. Bacteriol.
190: 5308-5317
[Abstract]
[Full Text]
-
Hoang, H. H., Gurich, N., Gonzalez, J. E.
(2008). Regulation of Motility by the ExpR/Sin Quorum-Sensing System in Sinorhizobium meliloti. J. Bacteriol.
190: 861-871
[Abstract]
[Full Text]