You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Expression of Arabidopsis CAX1 in Tobacco: Altered Calcium Homeostasis and Increased Stress Sensitivity
Kendal D. Hirschi
The Plant Cell
Vol. 11, No. 11 (Nov., 1999), pp. 2113-2122
Published by: American Society of Plant Biologists (ASPB)
Stable URL: http://www.jstor.org/stable/3871013
Page Count: 10
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Calcium ( Ca2+) efflux from the cytosol modulates Ca2+ concentrations in the cytosol, loads Ca2+ into intracellular compartments, and supplies Ca2+ to organelles to support biochemical functions. The Ca2+/ H+ antiporter CAX1 (for CALCIUM EXCHANGER 1) of Arabidopsis is thought to be a key mediator of these processes. To clarify the regulation of CAX1, we examined CAX1 RNA expression in response to various stimuli. CAX1 was highly expressed in response to exogenous Ca2+. Transgenic tobacco plants expressing CAX1 displayed symptoms of Ca2+ deficiencies, including hypersensitivity to ion imbalances, such as increased magnesium and potassium concentrations, and to cold shock, but increasing the Ca2+ in the media abrogated these sensitivities. Tobacco plants expressing CAX1 also demonstrated increased Ca2+ accumulation and altered activity of the tonoplast-enriched Ca2+/ H+ antiporter. These results emphasize that regulated expression of Ca2+/ H+ antiport activity is critical for normal growth and adaptation to certain stresses.
The Plant Cell © 1999 American Society of Plant Biologists (ASPB)