ENHANCED IRON (FE) UPTAKE BY SYNTHETIC SIDEROPHORES IN CORN ROOTS

The objective of this study was to investigate whether a specific siderophore-mediated iron uptake (possibly preceded by a reduction step) occurs in corn roots at a specific recognition site. The activity of ferrichrome analogs and ferrioxamine B, as iron carriers into corn roots, was studied. Stereo-specific recognition of Fe-ferrichrome analogs was observed during Fe uptake by corn roots. All ferrichrome analogs forming Fe(III) complexes of the same absolute configuration as does natural ferrichrome (LAMBDA-cis), enhance Fe uptake, while their enantiomers lack biological activity. Gallium (III) failed to be taken up under analogous conditions, indicating that synthetic ferrichrome analogs mediate the Fe uptake via a specific reduction step. Within certain limits, binding energy of the chelator did not play a role in enhancing iron uptake. It is suggested that the iron uptake mechanism in corn roots involves binding to a specific chiral receptor in conjunction with a reductive process.