Proteins under the Control of the Gene for Fe Efficiency in Tomato.

Fe-deficient dicotyledons develop Fe-efficiency reactions, such as proton extrusion and ferric chelate reduction activity, which are located in the plasma membranes of the root epidermal cells. The fer mutant of tomato (Lycopersicon esculentum Mill.) cannot develop these reactions. Membranes were isolated from roots of wild-type (FER) and mutant (fer) tomato plants grown on nutrient solution with high and low Fe concentrations. Two proteins were identified which are synthesized under the control of the FER gene.