Iron is an essential mineral nutrient required for virtually all forms of life. However, iron is potentially toxic when an excess amount of iron is present in the cell, or when iron is not in the proper location within the cell. Therefore, iron must be tightly controlled by delicate molecular mechanisms. Studying how iron is regulated in plants will not only provide fundamental scientific insights, but also provide potential strategies to enhance the nutritional quality of plants to improve agriculture and human nutrition. While caloric malnutrition has significantly decreased, malnutrition of essential mineral nutrients is still prevalent. In particular, iron deficiency affects nearly half of the world's population. Plants are the primary dietary source of iron worldwide, but they are not rich in iron. Biofortification, the process of enhancing the nutritional value of crops is a promising strategy that could provide a sustainable solution to malnutrition. Iron is a required nutrient for plants. However, because iron in the soil cannot readily be absorbed by plants, it is the third most limiting nutrient for plant growth. Therefore, the proposed work is of broad impact, as understanding iron transport in plants is key to improving plant growth, crop yields, and human nutrition. The project will provide research experiences for undergraduate students at Amherst College. In addition, an ongoing outreach activity to develop hands-on molecular biology modules for 5th graders at a local public elementary school will be supported by the project.
A key task in cellular iron homeostasis is to safely allocate iron to specific organelles for usage or storage. Mitochondria are of particular interest for iron nutrition. Essential metabolic processes, such as respiration, require iron, but mitochondria are highly susceptible to iron-induced oxidative damage. Despite the significance of iron in mitochondria, mitochondrial iron transport is not well understood in plants. The proposed work aims to understand iron homeostasis by investigating the role of a mitochondrial ferroportin (FPN) in Arabidopsis thaliana. FPNs are well-studied in vertebrates, yet hardly characterized in plants. Moreover, mitochondrial FPN is unique, as no other mitochondrial FPN has been identified. In this study, the directionality of iron transport will be investigated to test the hypothesis that FPN3 is a mitochondrial iron exporter. Ultimately, this study aims to understand the biological role of FPN3. Therefore, this study proposes to test if FPN3 release mitochondrial iron for use in the cytoplasm and/or for protection against oxidative stress, by analyzing fpn3 loss-of-function Arabidopsis mutants. The proposed work will unravel the cellular and physiological role of a mitochondrial FPN3 and contribute to a more comprehensive understanding of plant iron homeostasis.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
