In an attempt to characterize the membrane proteins responsible for Fe-phytosiderophore transport across the root plasmalemma of maize (Zea mays L.), maps of plasmalemma polypeptides were compared between the Fe-efficient maize cultivar Alice and the mutant ysl, which is defective in Fe-phytosiderophore uptake. Determination of the steady-state level of 580 polypeptides by computer-assisted image analysis of silver-stained 2D-gels enabled the identification of four polypeptides, with respective apparent molecular masses of 22.6 kDa, 25.6 kDa, 27.3 kDa and 43.8 kDa, which accumulated in response to iron-deficiency in the reference genotype Alice, but were under-represented in the mutant vsl Arguments in favour of role of these polypeptides in the transport of the Fe(III)-phytosiderophores across the root plasmalemma of maize are presented.