Iron is an essential nutrient for all higher plants, with iron-containing compounds figuring prominently in the electron transport systems of photosynthesis and respiration. Although iron is abundant in the soil, the acquisition of iron is problematic due to its low solubility at biological pH under aerobic conditions. Understanding how plants carry this important nutrient from soil into cells is critical for production of crops that would be richer sources of iron in foods. Since more than a third of the world's soils are iron-deficient, ability to develop plants that are more efficient in extracting iron from soil has important implications for agriculture globally.
Dartmouth researchers in collaboration with their colleagues at the University of Minnesota have identified IRT1 (iron-regulated transporter) gene encoding a probable Fe(II) transporter. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. The gene was cloned from Arabidopsis thaliana, a common weed in the mustard family, by functional expression in a yeast strain defective for iron uptake. In Arabidopsis, IRT1 is expressed in roots and is induced within 24 hours after transfer of plants to iron-deficient growth conditions. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. The novel transporter appears to draw the metal cadmium into cells as well. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans, suggesting it may be a member of a new family of genes involved in controlling the uptake of metals by cells.
Dartmouth scientists have already obtained the seeds from transgenic Arabidopsis plants engineered to overexpress the IRT1 gene and are preparing a series of experiments with these genetically engineered plants to monitor their ability to extract iron from iron-deficient soils. The IRT1 gene can also be used to increase the iron content of food.
This technology is claimed in the issued United States Patent Nos. 5,846,821, 6,162,900 and 6,590,140. We are seeking an industrial partner to further refine and market this technology. (Ref: J5)
Last Updated: 7/24/12