Abstract
Rice plants use a well-known phytosiderophore-based system (Strategy II). Recently, we showed that rice also possesses direct ferrous transport system. In spite of possessing these two systems, rice plants are extremely susceptible to low iron supply, because of low secretion of phytosiderophores and low activity of ferric reduction. The mutational reconstructed yeast ferric chelate reductase gene, refre1/372, was fused to the promoter of iron-regulated-transporter OsIRT1 promoter, and was introduced into rice plants. The transgene was expressed in response to low iron nutritional status in roots of transformants. Transgenic rice plants expressing the refre1/372 gene showed higher ferric chelate reductase activity and took iron up at higher rate than vector controls under iron-deficient conditions. Consequently, the transgenic rice plants showed an enhanced tolerance to low iron availability, and 7.9 times greater grain yields than that of the nontransformant rice on calcareous soils.
