Isolation and characterization of Fe(III)-chelate reductase gene LeFRO1 in tomato

Plant Mol Biol. 2004 Jan;54(1):125-36. doi: 10.1023/B:PLAN.0000028774.82782.16.

Abstract

Tomato is a model plant for studying molecular mechanisms of iron uptake and metabolism in strategy I plants (dicots and non-graminaceous monocots). Reduction of ferric to ferrous iron on the root surface is an obligatory process for iron acquisition from soil in these plants. LeFRO1 encoding an Fe(III)-chelate reductase protein was isolated from the tomato genome. We show that expression of LeFRO1 in yeast increases Fe(III)-chelate reductase activity. In a transient expression analysis we found that LeFRO1 protein was targeted on the plasma membrane. LeFRO1 transcript was detected in roots, leaves, cotyledons, flowers and young fruits by RT-PCR analysis. Abundance of LeFRO1 mRNA was much lower in young fruits than in other tissues. The transcription intensity of LeFRO1 in roots is dependent on the iron status whereas it is constitutively expressed in leaves. These results indicate that LeFRO1 is required in roots and shoots as well as in reproductive organs for iron homeostasis and that its transcription in roots and shoots is regulated by different control mechanisms. The expression of LeFRO1 was disrupted in the iron-inefficient mutants chloronerva and T3238 fer, indicating that FER and CHLN genes are involved in the regulation of LeFRO1 expression in tomato roots. The differential expression of LeFRO1 and LeIRT1 (an iron-regulated metal transporter gene in tomato) in roots of T3238 fer under iron-deficient and -sufficient conditions suggests that the FER gene may regulate expression of LeFRO1 more directly than that of LeIRT1 in tomato roots.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Blotting, Southern
  • Cell Nucleus / metabolism
  • Cytoplasm / metabolism
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • DNA, Complementary / isolation & purification
  • Exons
  • FMN Reductase / genetics*
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Plant
  • Genes, Plant / genetics
  • Genome, Plant
  • Green Fluorescent Proteins
  • Introns
  • Iron / deficiency
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Lycopersicon esculentum / enzymology
  • Lycopersicon esculentum / genetics*
  • Lycopersicon esculentum / metabolism
  • Microscopy, Confocal
  • Molecular Sequence Data
  • Mutation
  • Onions / cytology
  • Onions / genetics
  • Phylogeny
  • Plant Epidermis / cytology
  • Plant Epidermis / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Transfection

Substances

  • DNA, Complementary
  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Iron
  • FMN Reductase
  • ferric citrate iron reductase

Associated data

  • GENBANK/AY224079