FRD3, a member of the multidrug and toxin efflux family, controls iron deficiency responses in Arabidopsis.
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.
Rogers
Elizabeth E
EE
Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA. rogersee@missouri.edu
Guerinot
Mary Lou
ML
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
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