Rice Nicotianamine Synthase 2 Improves Iron and Zinc Levels in Wheat Grains

Micronutrients are essential in the human diet as they are required for key metabolic reactions and biological functions. A large fraction of the global human population suffers from micronutrient deficiencies, which has a negative impact on well-being and economic development. Biofortification of staple crops is a sustainable and effective approach to reduce health problems associated with micronutrient deficiencies.

Simrat Pal Singh of ETH Zurich and Switzerland, together with his colleagues, developed wheat lines expressing rice NICOTIANAMINE SYNTHASE 2 (OsNAS2) and bean FERRITIN (PvFERRITIN), both as single genes and in combination.The NAS gene catalyzes the synthesis of nicotianamine (NA), a precursor of the iron chelator deoxymugeneic acid (DMA) required for long distance iron translocation. On the other hand, FERRITIN is important for iron storage in plants.

Significant increases in iron and zinc content were observed in wheat grains of plants expressing either OsNAS2 or PvFERRTIN, or both genes. Specifically, wheat lines expressing OsNAS2 greatly surpass the target level of 30 percent dietary estimated average requirement (EAR) for iron, and 40 percent of EAR for zinc.

The wheat lines with significant levels of iron and zinc developed in this study could provide a useful germplasm for developing new wheat varieties that can reduce micronutrient deficiencies.

For more information, read the article in Theoretical and Applied Genetics.