Root-microbial effects on plant iron uptake from siderophores and phytosiderophores

• Published in: Plant and soil 1992-04, Vol.142 (1), p.1-7
• Main Authors: Crowley, D.E. (Texas Univ., Austin, TX (USA). Dept. of Microbiology), Roemheld, V, Marschner, H, Szaniszlo, P.J
• Format: Article
• Language: English
• Subjects: ABSORCION DE SUBSTANCIAS NUTRITIVAS; ABSORPTION DE SUBSTANCES NUTRITIVES; Acid soils; Agronomy. Soil science and plant productions; AVENA; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Corn; FER; Fundamental and applied biological sciences. Psychology; HIERRO; INOCULACION; INOCULATION; INOCULATION METHODS; IRON; Microbiology; MICROORGANISME; MICROORGANISMOS; MICROORGANISMS; NUTRIENT UPTAKE; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Phytosiderophores; Plant roots; Plants; PLANTULAS; PLANTULE; RACINE; RAICES; ROOTS; SEEDLINGS; Siderophores; SOIL; Soil microorganisms; Soil science; SOL; SUELO; ZEA MAYS
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/bf00010169

Collaborative experiments were conducted to determine whether microbial populations associated with plant roots may artifactually affect the rates of Fe uptake and translocation from microbial siderophores and phytosiderophores. Results showed nonaxenic maize to have 2 to 34-fold higher Fe-uptake rates than axenically grown plants when supplied with 1 µM Fe as either the microbial siderophore, ferrioxamine B (FOB), or the barley phytosiderophore, epi-hydroxymugineic acid (HMA). In experiments with nonsterile plants, inoculation of maize or oat seedlings with soil microorganisms and amendment of the hydroponic nutrient solutions with sucrose resulted in an 8-fold increase in FOB-mediated Fe-uptake rates by Fe-stressed maize and a 150-fold increase in FOB iron uptake rates by Fe-stressed oat, but had no effect on iron uptake by Fe-sufficient plants. Conversely, Fe-stressed maize and oat plants supplied with HMA showed decreased uptake and translocation in response to microbial inoculation and sucrose amendment. The ability of root-associated microorganisms to affect Fe-uptake rates from siderophores and phytosiderophores, even in short-term uptake experiments, indicates that microorganisms can be an unpredictable confounding factor in experiments examining mechanisms for utilization of microbial siderophores or phytosiderophores under nonsterile conditions.