This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Banta, L M Articles by Binns, A N Search for Related Content PubMed PubMed Citation Articles by Banta, L M Articles by Binns, A N

 Previous Article  |  Next Article 

J Bacteriol. 1994 June; 176(11): 3242-3249

research-article

Glu-255 outside the predicted ChvE binding site in VirA is crucial for sugar enhancement of acetosyringone perception by Agrobacterium tumefaciens.

Department of Biology, University of Pennsylvania, Philadelphia 19104-6018.

ABSTRACT

Transcriptional activation of the Agrobacterium tumefaciens vir regulon is regulated by phenolics such as acetosyringone (AS), certain monosaccharides, and acidic conditions produced by wounded plant cells. The transmembrane protein VirA acts as an environmental sensor, mediating signal transduction upon perception of these stimuli. Although the periplasmic domain of VirA is not absolutely required for AS-dependent vir gene induction, it is needed for interactions with the periplasmic sugar-binding protein ChvE that result in sugar-induced enhancement of phenolic sensitivity. In this report, we demonstrate that mutations within the periplasmic domain but outside the predicted ChvE binding region can drastically alter the sensitivity of VirA to As. Using site-directed mutagenesis, we have characterized the roles of three individual amino acids in sugar-dependent AS sensitivity and have correlated the induction phenotype with the tumorigenic capacity of strains expressing mutant versions of VirA. Substitution of leucine for Glu-255 abolishes sugar enhancement while replacement with aspartic acid results in a wild-type phenotype. This residue lies outside the predicted ChvE binding site and thus identifies a new region of the VirA periplasmic domain crucial for the enhancement of vir gene induction by carbohydrates. In the absence of inducing sugar, wild-type VirA protein appears to be subject to some form of inhibition that suppresses the maximal level of transcriptional activation; deletions within the periplasmic region relieve this suppression.

This article has been cited by other articles:

• Yuan, Z.-C., Liu, P., Saenkham, P., Kerr, K., Nester, E. W. (2008). Transcriptome Profiling and Functional Analysis of Agrobacterium tumefaciens Reveals a General Conserved Response to Acidic Conditions (pH 5.5) and a Complex Acid-Mediated Signaling Involved in Agrobacterium-Plant Interactions. J. Bacteriol. 190: 494-507 [Abstract] [Full Text]  
• Mascher, T., Helmann, J. D., Unden, G. (2006). Stimulus Perception in Bacterial Signal-Transducing Histidine Kinases. Microbiol. Mol. Biol. Rev. 70: 910-938 [Abstract] [Full Text]  
• Chevrot, R., Rosen, R., Haudecoeur, E., Cirou, A., Shelp, B. J., Ron, E., Faure, D. (2006). GABA controls the level of quorum-sensing signal in Agrobacterium tumefaciens. Proc. Natl. Acad. Sci. USA 103: 7460-7464 [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]  
• Suksomtip, M., Liu, P., Anderson, T., Tungpradabkul, S., Wood, D. W., Nester, E. W. (2005). Citrate Synthase Mutants of Agrobacterium Are Attenuated in Virulence and Display Reduced vir Gene Induction. J. Bacteriol. 187: 4844-4852 [Abstract] [Full Text]  
• Gao, R., Lynn, D. G. (2005). Environmental pH Sensing: Resolving the VirA/VirG Two-Component System Inputs for Agrobacterium Pathogenesis. J. Bacteriol. 187: 2182-2189 [Abstract] [Full Text]  
• Wise, A. A., Voinov, L., Binns, A. N. (2005). Intersubunit Complementation of Sugar Signal Transduction in VirA Heterodimers and Posttranslational Regulation of VirA Activity in Agrobacterium tumefaciens. J. Bacteriol. 187: 213-223 [Abstract] [Full Text]  
• Nair, G. R., Liu, Z., Binns, A. N. (2003). Reexamining the Role of the Accessory Plasmid pAtC58 in the Virulence of Agrobacterium tumefaciens Strain C58. Plant Physiol. 133: 989-999 [Abstract] [Full Text]  
• Liu, Z., Binns, A. N. (2003). Functional Subsets of the VirB Type IV Transport Complex Proteins Involved in the Capacity of Agrobacterium tumefaciens To Serve as a Recipient in virB-Mediated Conjugal Transfer of Plasmid RSF1010. J. Bacteriol. 185: 3259-3269 [Abstract] [Full Text]  
• Liu, Z., Jacobs, M., Schaff, D. A., McCullen, C. A., Binns, A. N. (2001). ChvD, a Chromosomally Encoded ATP-Binding Cassette Transporter-Homologous Protein Involved in Regulation of Virulence Gene Expression in Agrobacterium tumefaciens. J. Bacteriol. 183: 3310-3317 [Abstract] [Full Text]  
• Peng, W.-T., Lee, Y.-W., Nester, E. W. (1998). The Phenolic Recognition Profiles of the Agrobacterium tumefaciens VirA Protein Are Broadened by a High Level of the Sugar Binding Protein ChvE. J. Bacteriol. 180: 5632-5638 [Abstract] [Full Text]  
• Stahl, L. E., Jacobs, A., Binns, A. N. (1998). The Conjugal Intermediate of Plasmid RSF1010 Inhibits Agrobacterium tumefaciens Virulence and VirB-Dependent Export of VirE2. J. Bacteriol. 180: 3933-3939 [Abstract] [Full Text]