title: Maize yellow stripe1 encodes a membrane protein directly involved in Fe(III) uptake.
abstract: Frequently, crop plants do not take up adequate amounts of iron from the soil, leading to chlorosis, poor yield and decreased nutritional quality. Extremely limited soil bioavailability of iron has led plants to evolve two distinct uptake strategies: chelation, which is used by the world's principal grain crops; and reduction, which is used by other plant groups. The chelation strategy involves extrusion of low-molecular-mass secondary amino acids (mugineic acids) known as 'phytosiderophores' which chelate sparingly soluble iron. The Fe(III)-phytosiderophore complex is then taken up by an unknown transporter at the root surface. The maize yellow stripe1 (ys1) mutant is deficient in Fe(III)-phytosiderophore uptake, therefore YS1 has been suggested to be the Fe(III)-phytosiderophore transporter. Here we show that ys1 is a membrane protein that mediates iron uptake. Expression of YS1 in a yeast iron uptake mutant restores growth specifically on Fe(III)-phytosiderophore media. Under iron-deficient conditions, ys1 messenger RNA levels increase in both roots and shoots. Cloning of ys1 is an important step in understanding iron uptake in grasses, and has implications for mechanisms controlling iron homeostasis in all plants.
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Montpellier 2 et Ecole Nationale Supérieure d'Agronomie, France.
authors.forename: C
authors.initials: C
authors.lastname: Curie
authors.forename: Z
authors.initials: Z
authors.lastname: Panaviene
authors.forename: C
authors.initials: C
authors.lastname: Loulergue
authors.forename: S L
authors.initials: SL
authors.lastname: Dellaporta
authors.forename: J F
authors.initials: JF
authors.lastname: Briat
authors.forename: E L
authors.initials: EL
authors.lastname: Walker
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018744:DNA, Plant; D005290:Ferric Compounds / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D015698:Genomic Library; D007502:Iron Chelating Agents / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010940:Plant Proteins; D012441:Saccharomyces cerevisiae; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D018744:DNA, Plant; D005290:Ferric Compounds; D007502:Iron Chelating Agents; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010940:Plant Proteins; C419784:yellow stripe1 protein, Zea mays