The Thlaspi caerulescens NRAMP homologue TcNRAMP3 is capable of divalent cation transport

Mol Biotechnol. 2009 Jan;41(1):15-21. doi: 10.1007/s12033-008-9088-x. Epub 2008 Jul 29.

Abstract

The NRAMP gene family encodes integral membrane protein and mediates the transport of Fe, however, its function in transport of toxic metal ions is not very clear in plants. TcNRAMP3 was isolated from Thlaspi caerulescens, and encoded a metal transporter member of the NRAMP family. TcNRAMP3 was predominantly expressed in roots of T. caerulescens by semi-quantitative RT-PCR. The expression of TcNRAMP3 was induced by iron starvation and by the heavy metals Cd and Ni in roots. TcNRAMP3 was able to rescue growth of an iron uptake fet3fet4 mutant yeast strain, suggesting a possible role in iron transport. Expression of TcNRAMP3 in yeast increased Cd sensitivity and Cd content, while it enhanced the Ni resistance and reduced Ni accumulation, indicating that TcNRAMP3 could accumulate Cd and exclude Ni in yeast. Furthermore, overexpression of TcNRAMP3 in tobacco resulted in slight Cd sensitivity of root growth and did not influence Ni resistance. These results suggested that TcNRAMP3 played a role in metal cation homeostasis in plant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cadmium / metabolism
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism*
  • Cations, Divalent / metabolism*
  • Cloning, Molecular
  • Gene Dosage
  • Gene Expression Regulation, Fungal
  • Ion Transport
  • Iron / metabolism
  • Iron Deficiencies
  • Nickel / metabolism
  • Nicotiana / genetics
  • Nicotiana / metabolism
  • Phylogeny
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plant Roots / anatomy & histology
  • Plant Roots / genetics
  • Plant Roots / metabolism
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Polymerase Chain Reaction
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Stress, Physiological
  • Thlaspi / genetics
  • Thlaspi / metabolism*

Substances

  • Cation Transport Proteins
  • Cations, Divalent
  • Plant Proteins
  • natural resistance-associated macrophage protein 1
  • Cadmium
  • Nickel
  • Iron