Utilization by tomatoes of iron mediated by a siderophore produced by Rhizopus arrhizus

Abstract Rhizonus arrhizus was found to produce a novel siderophore named raphorin (Ra) when grown under Fe deficiency. Partially purified Fe‐Ra was found to alleviate Fe deficiency when applied to tomato plants grown in nutrient solutions buffered by either CaCO3 (pH 7.3) or HEPES (pH 7). Iron (55Fe) uptake rate by plants mediated by Ra, and translocation rate to the shoot, was almost as high as from 55FeEDDHA. It has been concluded the Fe‐Ra is a most efficient Fe source for plants when compared to other microbial sidero‐phores.