Iron and Zinc Enhancement in Rice Endosperm by Targeted and Synergistic Action of Genes

Iron deficiency anemia and zinc deficiency are among the most recognized forms of micronutrient malnutrition in humans. Various food fortification approaches have been suggested, but not many proved useful mainly due to socioeconomic or biological reasons. Monotonous diets based on staple cereals are frequently associated with human micronutrient malnutrition. Cereal grains constituting the most important basis of human food are in fact a poor source of iron and zinc. Biofortification of cereal grains, such as rice, has therefore emerged as a promising strategy. However, the variability for most micronutrients is very low in the rice germplasm and this does not leave traditional breeding alone to be a valid option for rice biofortification in many circumstances. Complementing the breeding efforts, gene technology offers perspectives for efficiently improving iron and zinc content in rice grain to dietary significant levels for human nutrition. In this chapter, the biotechnology strategies used to date in order to improve rice for iron and zinc content and the genes controlling iron and zinc homeostasis are reviewed.