Biofortified Zn and Fe Rice: Potential Contribution for Dietary Mineral and Human Health

Abstract

Iron (Fe) and zinc (Zn) deficiency constitute a major micronutrient deficiency around the globe, affecting rural populations residing in developing countries with minimum purchasing power and/or access to a diverse diet. Biofortification, the enrichment of staple food/crops with bioavailable micronutrients or vitamins in their edible parts, provides a potential sustainable solution towards such issues, in combination with other existing efforts. Utilisation of rice as a platform for the delivery of products biofortified with Fe and Zn could impact greatly the livelihood of people dependent on rice-based agri-food systems globally. The HarvestPlus and its partners have successfully supported the production, deployment and release of conventionally bred Zn-biofortified lines of rice and wheat in several countries; and also support potential innovative approaches such as genetic engineering and genome editing with higher Fe and Zn content in the grain. A large number of reviews on iron biofortification in rice has been published, in this review we summarise the Fe biofortification by transgenic approaches, but the major focus of this review is on the conventional and transgenic breeding efforts to generate Zn-biofortified lines in rice and discuss their potential to contribute in eradicating Zn deficiency, by examining bioavailability aspects, as well as the retention of Zn content in rice grains after cooking. We additionally examine the importance of a clear pathway for the successful delivery and large-scale adoption of high-Zn rice to achieve maximum impact.