Rice NICOTIANAMINE SYNTHASE 2 expression improves dietary iron and zinc levels in wheat

Simrat Pal Singh,Navreet K Bhullar,Beat Keller,Wilhelm Gruissem

doi:10.1007/s00122-016-2808-x

Simrat Pal Singh, Navreet K Bhullar + Show 2 more

Open Access

https://doi.org/10.1007/s00122-016-2808-x

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Abstract

Key messageIron and zinc deficiencies negatively impact human health worldwide. We developed wheat lines that meet or exceed recommended dietary target levels for iron and zinc in the grains. These lines represent useful germplasm for breeding new wheat varieties that can reduce iron and zinc deficiency-associated health burdens in the affected populations.Micronutrient deficiencies, including iron and zinc deficiencies, have negative impacts on human health globally. Iron-deficiency; anemia affects nearly two billion people worldwide and is the cause of reduced cognitive development, fatigue and overall low productivity. Similarly, zinc deficiency causes stunted growth, decreased immunity and increased risk of respiratory infections. Biofortification of staple crops is a sustainable and effective approach to reduce the burden of health problems associated with micronutrient deficiencies. Here, we developed wheat lines expressing rice NICOTIANAMINE SYNTHASE 2 (OsNAS2) and bean FERRITIN (PvFERRITIN) as single genes as well as in combination. NAS catalyzes the biosynthesis of nicotianamine (NA), which is a precursor of the iron chelator deoxymugeneic acid (DMA) required for long distance iron translocation. FERRITIN is important for iron storage in plants because it can store up to 4500 iron ions. We obtained significant increases of iron and zinc content in wheat grains of plants expressing either OsNAS2 or PvFERRTIN, or both genes. In particular, wheat lines expressing OsNAS2 greatly surpass the HarvestPlus recommended target level of 30 % dietary estimated average requirement (EAR) for iron, and 40 % of EAR for zinc, with lines containing 93.1 µg/g of iron and 140.6 µg/g of zinc in the grains. These wheat lines with dietary significant levels of iron and zinc represent useful germplasm for breeding new wheat varieties that can reduce micronutrient deficiencies in affected populations.

Highlights

Micronutrients are essential in the human diet because they are required for key metabolic reactions and biological functions
Children as well as pregnant and non-pregnant women are at a higher risk with approximately 43, 38 and 29 % of the population, respectively, 1 3
The PvFERRITIN cassette was excised from the PvFERRITIN-Pjet1.2 construct using KpnI and SmaI, and cloned into the OsNAS2-PbskII(−) construct, generating PvFERRITIN-OsNAS2

Summary

Introduction

Micronutrients are essential in the human diet because 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 (Muthayya et al 2013). Iron and zinc deficiencies are among the most widespread micronutrient deficiencies. IDA affects cognitive development, decreases immune function, and causes higher mortality of mothers and children at birth. Children as well as pregnant and non-pregnant women are at a higher risk with approximately 43, 38 and 29 % of the population, respectively, Theor Appl Genet (2017) 130:283–292 affected with IDA (Stevens et al 2013). Iron and zinc deficiencies are often associated with low micronutrient content in staple foods, poor micronutrient absorption from food, and dependence of the affected populations on simple and monotonous diets

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