This is a Career Advancement Award to support Dr. Guerinot's proposed research on iron uptake in the model higher plant, Arabidopsis thaliana, using biochemical, genetic, and molecular genetic approaches. Dr. Guerinot has long-standing interest in iron metabolism, and has until now focussed on iron uptake and metabolism in the Bradyrhizobium/soybean symbiosis, with particular emphasis on iron uptake and iron-stress physiology in the bacterial partner. She would like to expand her research to investigations of iron uptake and metabolism in the plant partner. To facilitate these studies, she has proposed to work on Arabidopsis as a model system, with the intention of ultimately transferring knowledge gained through these studies to studies of the soybean. It is anticipated that this new line of research will significantly enhance Dr. Guerinot's career.