Expression of arabidopsis CAX2 in tobacco. Altered metal accumulation and increased manganese tolerance

Plant Physiol. 2000 Sep;124(1):125-33. doi: 10.1104/pp.124.1.125.


Metal transport from the cytosol to the vacuole is thought to be an important component of ion tolerance and of a plant's potential for use in phytoremediation. The Arabidopsis antiporter CAX2 (calcium exchanger 2) may be a key mediator of this process. CAX2 expression in yeast suppressed both Ca(2+) and Mn(2+) growth defects. A peptide-specific antibody to the antiporter reacted with a 39-kD protein from plant vacuolar membranes. Tobacco (Nicotiana tabacum) plants expressing CAX2 accumulated more Ca(2+), Cd(2+), and Mn(2+) and were more tolerant to elevated Mn(2+) levels. Expression of CAX2 in tobacco increased Cd(2+) and Mn(2+) transport in isolated root tonoplast vesicles. These results suggest that CAX2 has a broad substrate range and modulation of this transporter may be an important component of future strategies to improve plant ion tolerance.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antiporters / genetics*
  • Antiporters / metabolism
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Biological Transport, Active
  • Blotting, Northern
  • Cadmium / metabolism
  • Calcium / metabolism
  • Calcium-Binding Proteins / genetics*
  • Calcium-Binding Proteins / metabolism
  • Cation Transport Proteins*
  • Cations, Divalent
  • Cells, Cultured
  • Cytosol / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Manganese / metabolism*
  • Phenotype
  • Plants, Genetically Modified
  • Plants, Toxic*
  • Tobacco / genetics*
  • Tobacco / metabolism
  • Vacuoles / metabolism*
  • Yeasts / genetics
  • Yeasts / metabolism


  • Antiporters
  • Calcium-Binding Proteins
  • Cation Transport Proteins
  • Cations, Divalent
  • calcium-hydrogen antiporters
  • Cadmium
  • Manganese
  • Calcium