title: Rice endosperm iron biofortification by targeted and synergistic action of nicotianamine synthase and ferritin.
abstract: 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.
authors.affiliation: Department of Biology, Plant Biotechnology, ETH Zurich, 8092 Zurich, Switzerland.
authors.forename: Judith
authors.initials: J
authors.lastname: Wirth
authors.forename: Susanna
authors.initials: S
authors.lastname: Poletti
authors.forename: Beat
authors.initials: B
authors.lastname: Aeschlimann
authors.forename: Nandadeva
authors.initials: N
authors.lastname: Yakandawala
authors.forename: Benedikt
authors.initials: B
authors.lastname: Drosse
authors.forename: Sonia
authors.initials: S
authors.lastname: Osorio
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tohge
authors.forename: Alisdair R
authors.initials: AR
authors.lastname: Fernie
authors.forename: Detlef
authors.initials: D
authors.lastname: Günther
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Gruissem
authors.forename: Christof
authors.initials: C
authors.lastname: Sautter
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism*; D005293:Ferritins / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D012639:Seeds / Q000235:genetics / Q000378:metabolism
chemical_list: D005293:Ferritins; D007501:Iron; D019883:Alkyl and Aryl Transferases; C118230:nicotianamine synthase