This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Boscari, A.
Right arrow Articles by Le Rudulier, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Boscari, A.
Right arrow Articles by Le Rudulier, D.

 Previous Article  |  Next Article 

Journal of Bacteriology, May 2002, p. 2654-2663, Vol. 184, No. 10
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.10.2654-2663.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

BetS Is a Major Glycine Betaine/Proline Betaine Transporter Required for Early Osmotic Adjustment in Sinorhizobium meliloti

Alexandre Boscari, Karine Mandon, Laurence Dupont, Marie-Christine Poggi, and Daniel Le Rudulier*

Laboratoire de Biologie Végétale et Microbiologie, CNRS FRE 2294, Faculté des Sciences, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cédex, France

Received 10 December 2001/ Accepted 12 February 2002

Hybridization to a PCR product derived from conserved betaine choline carnitine transporter (BCCT) sequences led to the identification of a 3.4-kb Sinorhizobium meliloti DNA segment encoding a protein (BetS) that displays significant sequence identities to the choline transporter BetT of Escherichia coli (34%) and to the glycine betaine transporter OpuD of Bacillus subtilis (30%). Although the BetS protein shows a common structure with BCCT systems, it possesses an unusually long hydrophilic C-terminal extension (169 amino acids). After heterologous expression of betS in E. coli mutant strain MKH13, which lacks choline, glycine betaine, and proline transport systems, both glycine betaine and proline betaine uptake were restored, but only in cells grown at high osmolarity or subjected to a sudden osmotic upshock. Competition experiments demonstrated that choline, ectoine, carnitine, and proline were not effective competitors for BetS-mediated betaine transport. Kinetic analysis revealed that BetS has a high affinity for betaines, with Kms of 16 ± 2 µM and 56 ± 6 µM for glycine betaine and proline betaine, respectively, in cells grown in minimal medium with 0.3 M NaCl. BetS activity appears to be Na+ driven. In an S. meliloti betS mutant, glycine betaine and proline betaine uptake was reduced by about 60%, suggesting that BetS represents a major component of the overall betaine uptake activities in response to salt stress. ß-Galactosidase activities of a betS-lacZ strain grown in various conditions showed that betS is constitutively expressed. Osmotic upshock experiments performed with wild-type and betS mutant cells, treated or not with chloramphenicol, indicated that BetS-mediated betaine uptake is the consequence of immediate activation of existing proteins by high osmolarity, most likely through posttranslational activation. Growth experiments underscored the crucial role of BetS as an emerging system involved in the rapid acquisition of betaines by S. meliloti subjected to osmotic upshock.

* Corresponding author. Mailing address: Laboratoire de Biologie Végétale et Microbiologie, CNRS FRE 2294, Faculté des Sciences, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cédex, France. Phone: (33) 492 076 834. Fax: (33) 492 076 838. E-mail: leruduli{at}unice.fr.

Journal of Bacteriology, May 2002, p. 2654-2663, Vol. 184, No. 10
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.10.2654-2663.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Chen, C., Beattie, G. A. (2008). Pseudomonas syringae BetT Is a Low-Affinity Choline Transporter That Is Responsible for Superior Osmoprotection by Choline over Glycine Betaine. J. Bacteriol. 190: 2717-2725 [Abstract] [Full Text]  
  • Chen, C., Beattie, G. A. (2007). Characterization of the Osmoprotectant Transporter OpuC from Pseudomonas syringae and Demonstration that Cystathionine-{beta}-Synthase Domains Are Required for Its Osmoregulatory Function. J. Bacteriol. 189: 6901-6912 [Abstract] [Full Text]  
  • Vriezen, J. A. C., de Bruijn, F. J., Nusslein, K. (2007). Responses of Rhizobia to Desiccation in Relation to Osmotic Stress, Oxygen, and Temperature. Appl. Environ. Microbiol. 73: 3451-3459 [Full Text]  
  • Tondervik, A., Strom, A. R. (2007). Membrane topology and mutational analysis of the osmotically activated BetT choline transporter of Escherichia coli. Microbiology 153: 803-813 [Abstract] [Full Text]  
  • Laloknam, S., Tanaka, K., Buaboocha, T., Waditee, R., Incharoensakdi, A., Hibino, T., Tanaka, Y., Takabe, T. (2006). Halotolerant Cyanobacterium Aphanothece halophytica Contains a Betaine Transporter Active at Alkaline pH and High Salinity. Appl. Environ. Microbiol. 72: 6018-6026 [Abstract] [Full Text]  
  • Alloing, G., Travers, I., Sagot, B., Le Rudulier, D., Dupont, L. (2006). Proline Betaine Uptake in Sinorhizobium meliloti: Characterization of Prb, an Opp-Like ABC Transporter Regulated by both Proline Betaine and Salinity Stress.. J. Bacteriol. 188: 6308-6317 [Abstract] [Full Text]  
  • Choquet, G., Jehan, N., Pissavin, C., Blanco, C., Jebbar, M. (2005). OusB, a Broad-Specificity ABC-Type Transporter from Erwinia chrysanthemi, Mediates Uptake of Glycine Betaine and Choline with a High Affinity. Appl. Environ. Microbiol. 71: 3389-3398 [Abstract] [Full Text]  
  • Jebbar, M., Sohn-Bosser, L., Bremer, E., Bernard, T., Blanco, C. (2005). Ectoine-Induced Proteins in Sinorhizobium meliloti Include an Ectoine ABC-Type Transporter Involved in Osmoprotection and Ectoine Catabolism. J. Bacteriol. 187: 1293-1304 [Abstract] [Full Text]  
  • Boscari, A., Mandon, K., Poggi, M.-C., Le Rudulier, D. (2004). Functional Expression of Sinorhizobium meliloti BetS, a High-Affinity Betaine Transporter, in Bradyrhizobium japonicum USDA110. Appl. Environ. Microbiol. 70: 5916-5922 [Abstract] [Full Text]  
  • Trinchant, J.-C., Boscari, A., Spennato, G., Van de Sype, G., Le Rudulier, D. (2004). Proline Betaine Accumulation and Metabolism in Alfalfa Plants under Sodium Chloride Stress. Exploring Its Compartmentalization in Nodules. Plant Physiol. 135: 1583-1594 [Abstract] [Full Text]  
  • Ly, A., Henderson, J., Lu, A., Culham, D. E., Wood, J. M. (2004). Osmoregulatory Systems of Escherichia coli: Identification of Betaine-Carnitine-Choline Transporter Family Member BetU and Distributions of betU and trkG among Pathogenic and Nonpathogenic Isolates. J. Bacteriol. 186: 296-306 [Abstract] [Full Text]  
  • Pflughoeft, K. J., Kierek, K., Watnick, P. I. (2003). Role of Ectoine in Vibrio cholerae Osmoadaptation. Appl. Environ. Microbiol. 69: 5919-5927 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»