Ferritins are major players in plant iron homeostasis. Surprisingly, their overexpression in transgenic plants led only to a moderate increase in seed iron content, suggesting the existence of control checkpoints for ...Ferritins are major players in plant iron homeostasis. Surprisingly, their overexpression in transgenic plants led only to a moderate increase in seed iron content, suggesting the existence of control checkpoints for iron loading and storage in seeds. This work reports the identification of two of these checkpoints. First, measurement of seed metal content during fruit development in Arabidopsis thaliana reveals a similar dynamic of loading for Fe, Mn, Cu, and Zn. The step controlling metal loading into the seed occurs by the regulation of transport from the hull to the seed. Second, metal loading and ferritin abundance were monitored in different genetic backgrounds affected in vacuolar iron transport （AtVIT1, AtNRAMP3, AtNRAMP4） or plastid iron storage （AtFER1 to 4）. This approach revealed （1） a post-translational reg- ulation of ferritin accumulation in seeds, and （2） that ferritin stability depends on the balance of iron allocation between vacuoles and plastids. Thus, the success of ferritin overexpression strategies for iron biofortification, a promising approach to reduce iron-deficiency anemia in developing countries, would strongly benefit from the identification and engineering of mechanisms enabling the translocation of high amounts of iron into seed plastids.展开更多
sequenced genome of a multicellular organism (Arabidopsis Genome, 2000) completed just after those of the nematode Caenorhabditis elegans (C. elegans Sequencing Consortium, 1998) and the fruit fly Drosophila melanogas...sequenced genome of a multicellular organism (Arabidopsis Genome, 2000) completed just after those of the nematode Caenorhabditis elegans (C. elegans Sequencing Consortium, 1998) and the fruit fly Drosophila melanogaster (Adams et al., 2000). Availability of a full whole-genome sequence for the reference plant opened to plant biologists what is commonly called the post-genomic era.展开更多
文摘Ferritins are major players in plant iron homeostasis. Surprisingly, their overexpression in transgenic plants led only to a moderate increase in seed iron content, suggesting the existence of control checkpoints for iron loading and storage in seeds. This work reports the identification of two of these checkpoints. First, measurement of seed metal content during fruit development in Arabidopsis thaliana reveals a similar dynamic of loading for Fe, Mn, Cu, and Zn. The step controlling metal loading into the seed occurs by the regulation of transport from the hull to the seed. Second, metal loading and ferritin abundance were monitored in different genetic backgrounds affected in vacuolar iron transport （AtVIT1, AtNRAMP3, AtNRAMP4） or plastid iron storage （AtFER1 to 4）. This approach revealed （1） a post-translational reg- ulation of ferritin accumulation in seeds, and （2） that ferritin stability depends on the balance of iron allocation between vacuoles and plastids. Thus, the success of ferritin overexpression strategies for iron biofortification, a promising approach to reduce iron-deficiency anemia in developing countries, would strongly benefit from the identification and engineering of mechanisms enabling the translocation of high amounts of iron into seed plastids.
文摘sequenced genome of a multicellular organism (Arabidopsis Genome, 2000) completed just after those of the nematode Caenorhabditis elegans (C. elegans Sequencing Consortium, 1998) and the fruit fly Drosophila melanogaster (Adams et al., 2000). Availability of a full whole-genome sequence for the reference plant opened to plant biologists what is commonly called the post-genomic era.
