| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Pseudomonas: Biology and Diversity |
University of California, Department of Plant and Microbial Biology, 111 Koshland Hall, Berkeley, CA 94720-3102, USA1
Author for correspondence: Steven E. Lindow. Tel: +1 510 642 4174. Fax: +1 510 642 4995. e-mail: icelab{at}socrates.berkeley.edu
Ferric iron is an essential element for microbial growth but its water solubility in aerobic environments is considered to be low. Thus it is a limiting resource for which microbes must compete in natural habitats. Since competition for iron occurs at the level of individual cells, knowledge of the variability in iron bioavailability to such individuals is required to assess the nature of the competition in these habitats. Ferric iron availability to cells of Pseudomonas syringae was assessed by quantifying the fluorescence intensity of single cells harbouring a plasmid-borne transcriptional fusion of an iron-regulated promoter from a locus encoding a membrane receptor for a pyoverdine siderophore with a reporter gene encoding green fluorescent protein (GFP) following fluorescence microscopy. Cells of this iron biosensor exhibited iron-dependent GFP fluorescence that was inversely proportional to the amount of iron added to the media, and which differed by over 20-fold in iron-replete compared to iron-deplete culture media. Cells cultured in a medium of a given iron content exhibited a very narrow range of fluorescence intensities. In contrast, the fluorescence intensity of cells of the biosensor strain recovered from the rhizosphere or phylloplane of inoculated bean plants varied greatly. The distribution of fluorescence intensities was strongly right-hand skewed, with about 10% of the cells exhibiting substantially higher GFP fluorescence than that of the median cell. Cells of a positive control strain, harbouring a fusion of the constitutive nptII promoter with the gfp reporter gene, exhibited uniform GFP fluorescence both in culture media and on plants. These results indicate that there is substantial heterogeneity of iron biovailability to cells of P. syringae on plants, with only a small subset of cells experiencing low iron availability. Such heterogeneity places constraints on models of interactions of bacteria in natural habitats that are based on competition for limited iron.
Keywords: FISH, Pseudomonas syringae, siderophore, ferric iron
Abbreviations: CCD, charge-coupled device; FISH, fluorescence in situ hybridization; GFP, green fluorescent protein; AMRA, tetramethylrhodamine-5-isothiocyanate
This article has been cited by other articles:
|
|
 |
|
  P. de Werra, E. Baehler, A. Huser, C. Keel, and M. Maurhofer Detection of Plant-Modulated Alterations in Antifungal Gene Expression in Pseudomonas fluorescens CHA0 on Roots by Flow Cytometry Appl. Envir. Microbiol., March 1, 2008; 74(5): 1339 - 1349. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Dulla and S. E. Lindow Quorum size of Pseudomonas syringae is small and dictated by water availability on the leaf surface PNAS, February 26, 2008; 105(8): 3082 - 3087. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X.-X. Zhang, A. George, M. J. Bailey, and P. B. Rainey The histidine utilization (hut) genes of Pseudomonas fluorescens SBW25 are active on plant surfaces, but are not required for competitive colonization of sugar beet seedlings Microbiology, June 1, 2006; 152(6): 1867 - 1875. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-M. Monier and S. E. Lindow Spatial Organization of Dual-Species Bacterial Aggregates on Leaf Surfaces Appl. Envir. Microbiol., September 1, 2005; 71(9): 5484 - 5493. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Brencic and S. C. Winans Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria Microbiol. Mol. Biol. Rev., March 1, 2005; 69(1): 155 - 194. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Bhatt and T. P. Denny Ralstonia solanacearum Iron Scavenging by the Siderophore Staphyloferrin B Is Controlled by PhcA, the Global Virulence Regulator J. Bacteriol., December 1, 2004; 186(23): 7896 - 7904. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. F. Brehm-Stecher and E. A. Johnson Single-Cell Microbiology: Tools, Technologies, and Applications Microbiol. Mol. Biol. Rev., September 1, 2004; 68(3): 538 - 559. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. E. Lindow and M. T. Brandl Microbiology of the Phyllosphere Appl. Envir. Microbiol., April 1, 2003; 69(4): 1875 - 1883. [Full Text] [PDF]
|
|
|
|
|
|
N. C. Casavant, G. A. Beattie, G. J. Phillips, and L. J. Halverson Site-Specific Recombination-Based Genetic System for Reporting Transient or Low-Level Gene Expression Appl. Envir. Microbiol., July 1, 2002; 68(7): 3588 - 3596. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. A. Holden, M. G. LaMontagne, A. K. Bruce, W. G. Miller, and S. E. Lindow Assessing the Role of Pseudomonas aeruginosa Surface-Active Gene Expression in Hexadecane Biodegradation in Sand Appl. Envir. Microbiol., May 1, 2002; 68(5): 2509 - 2518. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Stiner and L. J. Halverson Development and Characterization of a Green Fluorescent Protein-Based Bacterial Biosensor for Bioavailable Toluene and Related Compounds Appl. Envir. Microbiol., April 1, 2002; 68(4): 1962 - 1971. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. H. J. Leveau and S. E. Lindow Predictive and Interpretive Simulation of Green Fluorescent Protein Expression in Reporter Bacteria J. Bacteriol., December 1, 2001; 183(23): 6752 - 6762. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Koch, J. Worm, L. E. Jensen, O. Hojberg, and O. Nybroe Carbon Limitation Induces {sigma}S-Dependent Gene Expression in Pseudomonas fluorescens in Soil Appl. Envir. Microbiol., August 1, 2001; 67(8): 3363 - 3370. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. T. Brandl, B. Quinones, and S. E. Lindow Heterogeneous transcription of an indoleacetic acid biosynthetic gene in Erwinia herbicola on plant surfaces PNAS, March 13, 2001; 98(6): 3454 - 3459. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
