Abstract
The siderophore rhizoferrin, produced by the fungus Rhizopus arrhizus, was previously found to be as an efficient Fe source as Fe-ethylenediamine-di(o-hydroxphenylacetic acid) to strategy I plants. The role of this microbial siderophore in Fe uptake by strategy II plants is the focus of this research. Fe-rhizoferrin was found to be an efficient Fe source for barley (Hordeum vulgare L.) and corn (Zea mays L.). The mechanisms by which these Gramineae utilize Fe from Fe-rhizoferrin and from other chelators were studied. Fe uptake from 59Fe-rhizoferrin, 59Fe-ferrioxamine B, 59Fe-ethylenediaminetetraacetic acid, and 59Fe-2[prime]-deoxymugineic acid by barley plants grown in nutrient solution at pH 6.0 was examined during periods of high (morning) and low (evening) phytosiderophore release. Uptake and translocation rates from Fe chelates paralleled the diurnal rhythm of phytosiderophore release. In corn, however, similar uptake and translocation rates were observed both in the morning and in the evening. A constant rate of the phytosiderophore's release during 14 h of light was found in the corn cv Alice. The results presented support the hypothesis that Fe from Fe-rhizoferrin is taken up by strategy II plants via an indirect mechanism that involves ligand exchange between the ferrated microbial siderophore and phytosiderophores, which are then taken up by the plant. This hypothesis was verified by in vitro ligand-exchange experiments.
Full Text
The Full Text of this article is available as a PDF (886.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bar-Ness E., Hadar Y., Chen Y., Römheld V., Marschner H. Short-term effects of rhizosphere microorganisms on fe uptake from microbial siderophores by maize and oat. Plant Physiol. 1992 Sep;100(1):451–456. doi: 10.1104/pp.100.1.451. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bienfait H. F. Regulated redox processes at the plasmalemma of plant root cells and their function in iron uptake. J Bioenerg Biomembr. 1985 Apr;17(2):73–83. doi: 10.1007/BF00744199. [DOI] [PubMed] [Google Scholar]
- 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]
- Crowley D. E., Reid C. P., Szaniszlo P. J. Utilization of microbial siderophores in iron acquisition by oat. Plant Physiol. 1988 Jul;87(3):680–685. doi: 10.1104/pp.87.3.680. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guerinot M. L., Yi Y. Iron: Nutritious, Noxious, and Not Readily Available. Plant Physiol. 1994 Mar;104(3):815–820. doi: 10.1104/pp.104.3.815. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jurkevitch E., Hadar Y., Chen Y., Chino M., Mori S. Indirect utilization of the phytosiderophore mugineic acid as an iron source to rhizosphere fluorescent Pseudomonas. Biometals. 1993 Summer;6(2):119–123. doi: 10.1007/BF00140113. [DOI] [PubMed] [Google Scholar]
- 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]
- 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]
- Von Wiren N., Mori S., Marschner H., Romheld V. Iron Inefficiency in Maize Mutant ys1 (Zea mays L. cv Yellow-Stripe) Is Caused by a Defect in Uptake of Iron Phytosiderophores. Plant Physiol. 1994 Sep;106(1):71–77. doi: 10.1104/pp.106.1.71. [DOI] [PMC free article] [PubMed] [Google Scholar]