title: The tomato fer gene encoding a bHLH protein controls iron-uptake responses in roots.
abstract: Iron deficiency is among the most common nutritional disorders in plants. To cope with low iron supply, plants with the exception of the Gramineae increase the solubility and uptake of iron by inducing physiological and developmental alterations including iron reduction, soil acidification, Fe(II) transport and root-hair proliferation (strategy I). The chlorotic tomato fer mutant fails to activate the strategy I. It was shown previously that the fer gene is required in the root. Here, we show that fer plants exhibit root developmental phenotypes after low and sufficient iron nutrition indicating that FER acts irrespective of iron supply. Mutant fer roots displayed lower Leirt1 expression than wild-type roots. We isolated the fer gene by map-based cloning and demonstrate that it encodes a protein containing a basic helix-loop-helix domain. fer is expressed in a cell-specific pattern at the root tip independently from iron supply. Our results suggest that FER may control root physiology and development at a transcriptional level in response to iron supply and thus may be the first identified regulator for iron nutrition in plants.
authors.affiliation: Institute of Plant Genetics and Crop Plant Research, Correnstrasse 3, D-06466 Gatersleben, Germany.
authors.forename: Hong-Qing
authors.initials: HQ
authors.lastname: Ling
authors.forename: Petra
authors.initials: P
authors.lastname: Bauer
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Bereczky
authors.forename: Beat
authors.initials: B
authors.lastname: Keller
authors.forename: Martin
authors.initials: M
authors.lastname: Ganal
mesh_terms: D000595:Amino Acid Sequence; D001693:Biological Transport, Active / Q000235:genetics; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D005816:Genetic Complementation Test; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D017403:In Situ Hybridization; D007501:Iron / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D007501:Iron