To determine how overproduction of nicotianamine causes enhanced iron in grain, we will overexpress the Nicotianamine Synthase (NAS) gene in four distinct ways. First, we will overexpress the gene in all cells and tissues. This strategy works well in other cereal species, but has not been tested in corn. Next, we will express NAS in a phloem-specific, maternal transfer tissue-specific, and filial transfer tissue-specific manner. The phenotypes of all four types of plants will be analyzed. Phenotypic analysis will include gross appearance (iron deficiency chlorosis, stunting), details of gene expression in transgenic lines, and measurement of iron levels in tissues and fluids from the plants. The emphasis will be on examining grain micronutrient composition.