This Article Full Text Full Text (PDF) Other Versions of this Article: JB.01781-07v1 190/6/1997    most recent 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 Whitworth, D. E. Articles by Scanlan, D. J. Search for Related Content PubMed PubMed Citation Articles by Whitworth, D. E. Articles by Scanlan, D. J.

 Previous Article  |  Next Article 

Journal of Bacteriology, March 2008, p. 1997-2003, Vol. 190, No. 6
0021-9193/08/$08.00+0     doi:10.1128/JB.01781-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Phosphate Acquisition Components of the Myxococcus xanthus Pho Regulon Are Regulated by both Phosphate Availability and Development

Institute of Biological Sciences, Cledwyn Building, Aberystwyth University, Ceredigion SY23 3DD, United Kingdom,¹ Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom²

Received 10 November 2007/ Accepted 26 December 2007

In many organisms, phosphatase expression and phosphate (P) uptake are coordinately regulated by the Pho regulon. In Myxococcus xanthus P limitation initiates multicellular development, a process associated with changes in phosphatase expression. We sought here to characterize the link between P acquisition and development in this bacterium, an organism capable of preying upon other microorganisms as a sole nutrient source. M. xanthus seems to possess no significant internal P stores, as reducing the P concentration to less than 10 µM retarded growth within one doubling time. Pyrophosphate, polyphosphate, and glyceraldehyde-3-phosphate could support growth as sole P sources, although many other P-containing biomolecules could not (including nucleic acids and phospholipids). Several Pho regulon promoters were found to be highly active during vegetative growth, and P limitation specifically induced pstSCAB, AcPA1, and pho3 promoter activity and repressed pit expression. Enhanced pstSCAB and pho3 promoter activities in a phoP4 mutant (in the presence of high and low concentrations of P) suggested that PhoP4 acts as a repressor of these genes. However, in a phoP4 background, the activities of pstSCAB remained P regulated, suggesting that there is additional regulation by a P-sensitive factor. Initiation of multicellular development caused immediate down-regulation of Pho regulon genes and caused pstSCAB and pho3 promoter activities to become P insensitive. Hence, P acquisition components of the M. xanthus Pho regulon are regulated by both P availability and development, with developmental down-regulation overriding up-regulation by P limitation. These observations suggest that when development is initiated, subsequent changes in P availability become irrelevant to the population, which presumably has sufficient intrinsic P to ensure completion of the developmental program.

Published ahead of print on 4 January 2008.

This article has been cited by other articles:

• Santos-Beneit, F., Rodriguez-Garcia, A., Franco-Dominguez, E., Martin, J. F. (2008). Phosphate-dependent regulation of the low- and high-affinity transport systems in the model actinomycete Streptomyces coelicolor. Microbiology 154: 2356-2370 [Abstract] [Full Text]