title: FRD3, a member of the multidrug and toxin efflux family, controls iron deficiency responses in Arabidopsis.
abstract: We present the cloning and characterization of an Arabidopsis gene, FRD3, involved in iron homeostasis. Plants carrying any of the three alleles of frd3 constitutively express three strategy I iron deficiency responses and misexpress a number of iron deficiency-regulated genes. Mutant plants also accumulate approximately twofold excess iron, fourfold excess manganese, and twofold excess zinc in their shoots. frd3-3 was first identified as man1. The FRD3 gene is expressed at detectable levels in roots but not in shoots and is predicted to encode a membrane protein belonging to the multidrug and toxin efflux family. Other members of this family have been implicated in a variety of processes and are likely to transport small organic molecules. The phenotypes of frd3 mutant plants, which are consistent with a defect in either iron deficiency signaling or iron distribution, indicate that FRD3 is an important component of iron homeostasis in Arabidopsis.
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA. rogersee@missouri.edu
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Rogers
authors.forename: Mary Lou
authors.initials: ML
authors.lastname: Guerinot
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology; D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001692:Biological Transport / Q000235:genetics / Q000502:physiology; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018432:Drug Resistance, Multiple / Q000235:genetics; D038181:FMN Reductase / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D007501:Iron / Q000378:metabolism; D000090463:Iron Deficiencies; D008345:Manganese / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics / Q000502:physiology; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014118:Toxins, Biological / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C469252:FRD3 protein, Arabidopsis; D026901:Membrane Transport Proteins; D014118:Toxins, Biological; C082893:nicotianamine; D008345:Manganese; D001383:Azetidinecarboxylic Acid; D007501:Iron; D038181:FMN Reductase; C023903:ferric citrate iron reductase; D015032:Zinc