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Metabolic engineering of bread wheat improves grain iron concentration and bioavailability

2019; Wiley; Volume: 17; Issue: 8 Linguagem: Inglês

10.1111/pbi.13074

1467-7652

Jesse T. Beasley, Julien Bonneau, José Tonatiuh Sánchez-Palacios, Laura T. Moreno‐Moyano, Damien L. Callahan, Elad Tako, Raymond P. Glahn, Enzo Lombi, Alexander Johnson,

Cassava research and cyanide

Summary Bread wheat ( Triticum aestivum L.) is cultivated on more land than any other crop and produces a fifth of the calories consumed by humans. Wheat endosperm is rich in starch yet contains low concentrations of dietary iron (Fe) and zinc (Zn). Biofortification is a micronutrient intervention aimed at increasing the density and bioavailability of essential vitamins and minerals in staple crops; Fe biofortification of wheat has proved challenging. In this study we employed constitutive expression ( CE ) of the rice ( Oryza sativa L.) nicotianamine synthase 2 ( Os NAS 2 ) gene in bread wheat to up‐regulate biosynthesis of two low molecular weight metal chelators – nicotianamine ( NA ) and 2′‐deoxymugineic acid ( DMA ) – that play key roles in metal transport and nutrition. The CE ‐ Os NAS 2 plants accumulated higher concentrations of grain Fe, Zn, NA and DMA and synchrotron X‐ray fluorescence microscopy ( XFM ) revealed enhanced localization of Fe and Zn in endosperm and crease tissues, respectively. Iron bioavailability was increased in white flour milled from field‐grown CE ‐ Os NAS 2 grain and positively correlated with NA and DMA concentrations.