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 Chen, C.
Right arrow Articles by Beattie, G. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chen, C.
Right arrow Articles by Beattie, G. A.

 Previous Article  |  Next Article 

Journal of Bacteriology, April 2008, p. 2717-2725, Vol. 190, No. 8
0021-9193/08/$08.00+0     doi:10.1128/JB.01585-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Pseudomonas syringae BetT Is a Low-Affinity Choline Transporter That Is Responsible for Superior Osmoprotection by Choline over Glycine Betaine{triangledown}

Chiliang Chen and Gwyn A. Beattie*

Department of Plant Pathology, Iowa State University, Ames, Iowa 50011-3211

Received 30 September 2007/ Accepted 12 December 2007

The plant pathogen Pseudomonas syringae derives better osmoprotection from choline than from glycine betaine, unlike most bacteria that have been characterized. In this report, we identified a betaine/carnitine/choline family transporter (BCCT) in P. syringae pv. tomato strain DC3000 that mediates the transport of choline and acetylcholine. This transporter has a particularly low affinity (Km of 876 µM) and high capacity (Vmax of 80 nmol/min/mg of protein) for choline transport relative to other known BCCTs. Although BetT activity increased in response to hyperosmolarity, BetT mediated significant uptake under low-osmolarity conditions, suggesting a role in transport for both osmoprotection and catabolism. Growth studies with mutants deficient in BetT and other choline transporters demonstrated that BetT was responsible for the superior osmoprotection conferred to P. syringae by choline over glycine betaine when these compounds were provided at high concentrations (>100 µM). These results suggest that P. syringae has evolved to survive in relatively choline-rich habitats, a prediction that is supported by the common association of P. syringae with plants and the widespread production of choline, but genus- and species-specific production of glycine betaine, by plants. Among the three putative BCCT family transporters in Pseudomonas aeruginosa and six in Pseudomonas putida, different transporters were predicted to function based on similarity to Escherichia coli BetT than to P. syringae BetT. Functional P. putida and P. aeruginosa transporters were identified, and their possession of a long C-terminal tail suggested an osmoregulatory function for this tail; this function was confirmed for P. syringae BetT using deletion derivatives.

* Corresponding author. Mailing address: Iowa State University, Department of Plant Pathology, 207 Science I, Ames, IA 50011-3211. Phone: (515) 294-5571. Fax: (515) 294-6019. E-mail: gbeattie{at}iastate.edu

{triangledown} Published ahead of print on 21 December 2007.

Journal of Bacteriology, April 2008, p. 2717-2725, Vol. 190, No. 8
0021-9193/08/$08.00+0     doi:10.1128/JB.01585-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Goldberg, J. B., Hancock, R. E. W., Parales, R. E., Loper, J., Cornelis, P. (2008). Pseudomonas 2007. J. Bacteriol. 190: 2649-2662 [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»