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 Suksomtip, M.
Right arrow Articles by Nester, E. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Suksomtip, M.
Right arrow Articles by Nester, E. W.

 Previous Article  |  Next Article 

Journal of Bacteriology, July 2005, p. 4844-4852, Vol. 187, No. 14
0021-9193/05/$08.00+0     doi:10.1128/JB.187.14.4844-4852.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Citrate Synthase Mutants of Agrobacterium Are Attenuated in Virulence and Display Reduced vir Gene Induction

Maneewan Suksomtip ,{dagger},{ddagger} Pu Liu,{dagger} Tamara Anderson,§ Sumalee Tungpradabkul,{ddagger} Derek W. Wood, and Eugene W. Nester*

Department of Microbiology, Box 357242, University of Washington, Seattle, Washington 98195-7242

Received 7 January 2005/ Accepted 16 March 2005

A citrate synthase (CS) deletion mutant of Agrobacterium tumefaciens C58 is highly attenuated in virulence. The identity of the mutant was initially determined from its amino acid sequence, which is 68% identical to Escherichia coli and 77% identical to Brucella melitensis. The mutant lost all CS enzymatic activity, and a cloned CS gene complemented a CS mutation in Sinorhizobium. The CS mutation resulted in a 10-fold reduction in vir gene expression, which likely accounts for the attenuated virulence. When a plasmid containing a constitutive virG [virG(Con)] locus was introduced into this mutant, the level of vir gene induction was restored to nearly wild-type level. Further, the virG(Con)-complemented CS mutant strain induced tumors that were similar in size and number to those induced by the parental strain. The CS mutation resulted in only a minor reduction in growth rate in a glucose-salts medium. Both the CS mutant and the virG(Con)-complemented CS strain displayed similar growth deficiencies in a glucose-salts medium, indicating that the reduced growth rate of the CS mutant could not be responsible for the attenuated virulence. A search of the genome of A. tumefaciens C58 revealed four proteins, encoded on different replicons, with conserved CS motifs. However, only the locus that when mutated resulted in an attenuated phenotype has CS activity. Mutations in the other three loci did not result in attenuated virulence and any loss of CS activity, and none were able to complement the CS mutation in Sinorhizobium. The function of these loci remains unknown.

* Corresponding author. Mailing address: Department of Microbiology, Box 357242, University of Washington, Seattle, WA 98195-7242. Phone: (206) 616-8588. Fax: (206) 543-8297. E-mail: gnester{at}u.washington.edu.

{dagger} M.S. and P.L. have contributed equally to this work.

{ddagger} Present address: Dept. of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.

§ Present address: Fred Hutchinson Cancer Research Center, Basic Sciences Division, B2-135, 1100 Fairview Avenue North, Seattle, WA 98109.

Present address: Department of Biology, 3307 3rd Ave. W., Suite 205, Seattle Pacific University, Seattle, WA 98119.

Journal of Bacteriology, July 2005, p. 4844-4852, Vol. 187, No. 14
0021-9193/05/$08.00+0     doi:10.1128/JB.187.14.4844-4852.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Ngok-Ngam, P., Ruangkiattikul, N., Mahavihakanont, A., Virgem, S. S., Sukchawalit, R., Mongkolsuk, S. (2009). Roles of Agrobacterium tumefaciens RirA in Iron Regulation, Oxidative Stress Response, and Virulence. J. Bacteriol. 191: 2083-2090 [Abstract] [Full Text]  
  • Beare, P. A., Howe, D., Cockrell, D. C., Omsland, A., Hansen, B., Heinzen, R. A. (2009). Characterization of a Coxiella burnetii ftsZ Mutant Generated by Himar1 Transposon Mutagenesis. J. Bacteriol. 191: 1369-1381 [Abstract] [Full Text]  
  • Saenkham, P., Eiamphungporn, W., Farrand, S. K., Vattanaviboon, P., Mongkolsuk, S. (2007). Multiple Superoxide Dismutases in Agrobacterium tumefaciens: Functional Analysis, Gene Regulation, and Influence on Tumorigenesis. J. Bacteriol. 189: 8807-8817 [Abstract] [Full Text]  
  • Liu, P., Wood, D., Nester, E. W. (2005). Phosphoenolpyruvate Carboxykinase Is an Acid-Induced, Chromosomally Encoded Virulence Factor in Agrobacterium tumefaciens. J. Bacteriol. 187: 6039-6045 [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»