title: The Arabidopsis YELLOW STRIPE LIKE4 and 6 transporters control iron release from the chloroplast.
abstract: In most plant cell types, the chloroplast represents the largest sink for iron, which is both essential for chloroplast metabolism and prone to cause oxidative damage. Here, we show that to buffer the potentially harmful effects of iron, besides ferritins for storage, the chloroplast is equipped with specific iron transporters that respond to iron toxicity by removing iron from the chloroplast. We describe two transporters of the YELLOW STRIPE1-LIKE family from Arabidopsis thaliana, YSL4 and YSL6, which are likely to fulfill this function. Knocking out both YSL4 and YSL6 greatly reduces the plant's ability to cope with excess iron. Biochemical and immunolocalization analyses showed that YSL6 resides in the chloroplast envelope. Elemental analysis and histochemical staining indicate that iron is trapped in the chloroplasts of the ysl4 ysl6 double mutants, which also accumulate ferritins. Also, vacuolar iron remobilization and NRAMP3/4 expression are inhibited. Furthermore, ubiquitous expression of YSL4 or YSL6 dramatically reduces plant tolerance to iron deficiency and decreases chloroplastic iron content. These data demonstrate a fundamental role for YSL4 and YSL6 in managing chloroplastic iron. YSL4 and YSL6 expression patterns support their physiological role in detoxifying iron during plastid dedifferentiation occurring in embryogenesis and senescence.
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5004/Institut National de la Recherche Agronomique/SupAgro/Université Montpellier 1, F-34060 Montpellier cedex 2, France.
authors.forename: Fanchon
authors.initials: F
authors.lastname: Divol
authors.forename: Daniel
authors.initials: D
authors.lastname: Couch
authors.forename: Geneviève
authors.initials: G
authors.lastname: Conéjéro
authors.forename: Hannetz
authors.initials: H
authors.lastname: Roschzttardtz
authors.forename: Stéphane
authors.initials: S
authors.lastname: Mari
authors.forename: Catherine
authors.initials: C
authors.lastname: Curie
mesh_terms: D000220:Adaptation, Biological; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D016922:Cellular Senescence; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005293:Ferritins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D007501:Iron / Q000378:metabolism*; D010641:Phenotype; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D060365:Chloroplast Proteins; C408073:NRAMP4 protein, Arabidopsis; C408072:Nramp3 protein, Arabidopsis; D005293:Ferritins; D007501:Iron