Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1988 Jul;87(3):680–685. doi: 10.1104/pp.87.3.680

Utilization of Microbial Siderophores in Iron Acquisition by Oat 1

David E Crowley 1,2, C P Patrick Reid 1,2, Paul J Szaniszlo 1,2
PMCID: PMC1054820  PMID: 16666207

Abstract

Iron uptake by oat (Avena sativa cv Victory) was examined under hydroponic chemical conditions that required direct utilization of microbial siderophores for iron transport. Measurements of iron uptake rates by excised roots from the hydroxamate siderophores, ferrichrome, ferrichrome A, coprogen, ferrioxamine B (FOB), and rhodotorulic acid (RA) showed all five of the siderophores supplied iron, but that FOB and RA were preferentially utilized. FOB-mediated iron uptake increased four-fold when roots were preconditioned to iron stress and involved an active, iron-stress induced transport system that was inhibited by 5 millimolar sodium azide or 0.5 millimolar dinitrophenol. Kinetic studies indicated partial saturation with an apparent Km of 5 micromolar when FOB was supplied at 0.1 to 50 micromolar concentrations. Whole plant experiments confirmed that 5 micromolar FOB was sufficient for plant growth. Siderophore-mediated iron transport was inhibited by Cr-ferrichrome, an analog of ferrated siderophore. Our results confirm the existence of a microbial siderophore iron transport system in oat which functions within the physiological concentrations produced and used by soil microorganisms.

Full text

PDF
685

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Becker J. O., Hedges R. W., Messens E. Inhibitory effect of pseudobactin on the uptake of iron by higher plants. Appl Environ Microbiol. 1985 May;49(5):1090–1093. doi: 10.1128/aem.49.5.1090-1093.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bienfait H. F., van den Briel W., Mesland-Mul N. T. Free space iron pools in roots: generation and mobilization. Plant Physiol. 1985 Jul;78(3):596–600. doi: 10.1104/pp.78.3.596. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Cline G. R., Reid C. P., Powell P. E., Szaniszlo P. J. Effects of a hydroxamate siderophore on iron absorption by sunflower and sorghum. Plant Physiol. 1984 Sep;76(1):36–39. doi: 10.1104/pp.76.1.36. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Ecker D. J., Emery T. Iron uptake from ferrichrome A and iron citrate in Ustilago sphaerogena. J Bacteriol. 1983 Aug;155(2):616–622. doi: 10.1128/jb.155.2.616-622.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Müller G., Barclay S. J., Raymond K. N. The mechanism and specificity of iron transport in Rhodotorula pilimanae probed by synthetic analogs of rhodotorulic acid. J Biol Chem. 1985 Nov 15;260(26):13916–13920. [PubMed] [Google Scholar]
  6. Müller G., Matzanke B. F., Raymond K. N. Iron transport in Streptomyces pilosus mediated by ferrichrome siderophores, rhodotorulic acid, and enantio-rhodotorulic acid. J Bacteriol. 1984 Oct;160(1):313–318. doi: 10.1128/jb.160.1.313-318.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Neilands J. B. Microbial envelope proteins related to iron. Annu Rev Microbiol. 1982;36:285–309. doi: 10.1146/annurev.mi.36.100182.001441. [DOI] [PubMed] [Google Scholar]
  8. Römheld V., Marschner H. Evidence for a specific uptake system for iron phytosiderophores in roots of grasses. Plant Physiol. 1986 Jan;80(1):175–180. doi: 10.1104/pp.80.1.175. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Römheld V., Marschner H. Mechanism of iron uptake by peanut plants : I. Fe reduction, chelate splitting, and release of phenolics. Plant Physiol. 1983 Apr;71(4):949–954. doi: 10.1104/pp.71.4.949. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Wiebe C., Winkelmann G. Kinetic studies on the specificity of chelate-iron uptake in Aspergillus. J Bacteriol. 1975 Sep;123(3):837–842. doi: 10.1128/jb.123.3.837-842.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES