Expression of arabidopsis CAX2 in tobacco. Altered metal accumulation and increased manganese tolerance.
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.
Hirschi
K D
KD
Baylor College of Medicine, Plant Physiology Group, United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Houston, Texas 77030, USA. kendalh@bcm.tmc.edu
Korenkov
V D
VD
Wilganowski
N L
NL
Wagner
G J
GJ
D017920:Antiporters / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D001693:Biological Transport, Active; D015152:Blotting, Northern; D002104:Cadmium / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D027682:Cation Transport Proteins; D002413:Cations, Divalent; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008345:Manganese / Q000378:metabolism*; D010641:Phenotype; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism*; D015003:Yeasts / Q000235:genetics / Q000378:metabolism
D017920:Antiporters; D002135:Calcium-Binding Proteins; D027682:Cation Transport Proteins; D002413:Cations, Divalent; C027614:calcium-hydrogen antiporters; D002104:Cadmium; D008345:Manganese; D002118:Calcium