This Article Full Text 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 Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Danhorn, T. Articles by Fuqua, C. Search for Related Content PubMed PubMed Citation Articles by Danhorn, T. Articles by Fuqua, C.

Phosphorus Limitation Enhances Biofilm Formation of the Plant Pathogen Agrobacterium tumefaciens through the PhoR-PhoB Regulatory System

Department of Biology, Indiana University, Bloomington, Indiana 47405,¹ Biocentrum-DTU, Technical University of Denmark, DK-2800 Lyngby, Denmark,² Department of Microbiology, University of Iowa, Iowa City, Iowa 52242³

Received 11 November 2003/ Accepted 26 February 2004

The plant pathogen Agrobacterium tumefaciens forms architecturally complex biofilms on inert surfaces. Adherence of A. tumefaciens C58 was significantly enhanced under phosphate limitation compared to phosphate-replete conditions, despite slower overall growth under low-phosphate conditions. Replacement of P_i with sn-glycerol-3-phosphate and 2-aminoethylphosphonate yielded similar results. The increase in surface interactions under phosphate limitation was observed in both static culture and continuous-culture flow cells. Statistical analysis of confocal micrographs obtained from the flow cell biofilms revealed that phosphate limitation increased both the overall attached biomass and the surface coverage, whereas the maximum thickness of the biofilm was not affected. Functions encoded on the two large plasmids of A. tumefaciens C58, pTiC58 and pAtC58, were not required for the observed phosphate effect. The phosphate concentration at which increased attachment was observed triggered the phosphate limitation response, controlled in many bacteria by the two-component regulatory system PhoR-PhoB. The A. tumefaciens phoB and phoR orthologues could only be disrupted in the presence of plasmid-borne copies of the genes, suggesting that this regulatory system might be essential. Expression of the A. tumefaciens phoB gene from a tightly regulated inducible promoter, however, correlated with the amount of biofilm under both phosphate-limiting and nonlimiting conditions, demonstrating that components of the Pho regulon influence A. tumefaciens surface interactions.

This article has been cited by other articles:

• Merritt, P. M., Danhorn, T., Fuqua, C. (2007). Motility and Chemotaxis in Agrobacterium tumefaciens Surface Attachment and Biofilm Formation. J. Bacteriol. 189: 8005-8014 [Abstract] [Full Text]  
• Yuan, Z.-C., Zaheer, R., Finan, T. M. (2006). Regulation and Properties of PstSCAB, a High-Affinity, High-Velocity Phosphate Transport System of Sinorhizobium meliloti. J. Bacteriol. 188: 1089-1102 [Abstract] [Full Text]  
• Farah, C., Vera, M., Morin, D., Haras, D., Jerez, C. A., Guiliani, N. (2005). Evidence for a Functional Quorum-Sensing Type AI-1 System in the Extremophilic Bacterium Acidithiobacillus ferrooxidans. Appl. Environ. Microbiol. 71: 7033-7040 [Abstract] [Full Text]  
• Sauer, K., Cullen, M. C., Rickard, A. H., Zeef, L. A. H., Davies, D. G., Gilbert, P. (2004). Characterization of Nutrient-Induced Dispersion in Pseudomonas aeruginosa PAO1 Biofilm. J. Bacteriol. 186: 7312-7326 [Abstract] [Full Text]