• Open Access

Rice endosperm iron biofortification by targeted and synergistic action of nicotianamine synthase and ferritin

Authors

  • Judith Wirth,

    1. Department of Biology, Plant Biotechnology, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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    • Present address: Federal Research Station Agroscope Changins-Wädenswil ACW, PO Box 1012, 1260 Nyon, Switzerland

  • Susanna Poletti,

    1. Department of Biology, Plant Biotechnology, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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    • Present address: International Rice Research Institute (IRRI), Plant Breeding, Genetics and Biotechnology, Los Baños, Laguna, Philippines

  • Beat Aeschlimann,

    1. Department of Chemistry and Applied Biology, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
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  • Nandadeva Yakandawala,

    1. Department of Biology, Plant Biotechnology, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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    • §

      Present address: Kane Biotech Inc., 5–1250 Waverle Street, Winnipeg, MB, Canada, R3T 6C6

  • Benedikt Drosse,

    1. Department of Biology, Plant Biotechnology, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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  • Sonia Osorio,

    1. Max-Planck-Institut for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam OT, Golm, Germany
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  • Takayuki Tohge,

    1. Max-Planck-Institut for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam OT, Golm, Germany
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  • Alisdair R. Fernie,

    1. Max-Planck-Institut for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam OT, Golm, Germany
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  • Detlef Günther,

    1. Department of Chemistry and Applied Biology, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
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  • Wilhelm Gruissem,

    Corresponding author
    1. Department of Biology, Plant Biotechnology, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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  • Christof Sautter

    Corresponding author
    1. Department of Biology, Plant Biotechnology, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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* Correspondence (fax +41.44.632 1079; e-mail wgruissem@ethz.ch, csautter@ethz.ch)

Summary

Nearly one-third of the world's population, mostly women and children, suffer from iron malnutrition and its consequences, such as anaemia or impaired mental development. Iron fortification of food is difficult because soluble iron is either unstable or unpalatable, and non-soluble iron is not bioavailable. Genetic engineering of crop plants to increase iron content has therefore emerged as an alternative for iron biofortification. To date, strategies to increase iron content have relied on single genes, with limited success. Our work focuses on rice as a model plant, because it feeds one-half of the world's population, including the majority of the iron-malnourished population. Using the targeted expression of two transgenes, nicotianamine synthase and ferritin, we increased the iron content of rice endosperm by more than six-fold. Analysis of transgenic rice lines confirmed that, in combination, they provide a synergistic effect on iron uptake and storage. Laser ablation-inductively coupled plasma-mass spectrometry showed that the iron in the endosperm of the transgenic rice lines accumulated in spots, most probably as a consequence of spatially restricted ferritin accumulation. Agronomic evaluation of the high-iron rice lines did not reveal a yield penalty or significant changes in trait characters, except for a tendency to earlier flowering. Overall, we have demonstrated that rice can be engineered with a small number of genes to achieve iron biofortification at a dietary significant level.

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