Related Experiment Videos
The plant vacuolar Na+/H+ antiport
B J Barkla1, M P Apse, M F Manolson
1Department of Botany, University of Toronto, ON, Canada.
Symposia of the Society for Experimental Biology
|January 1, 1994
Summary
Salt-tolerant plants use vacuolar compartmentalization to manage sodium. A 170 kDa tonoplast protein is linked to the sodium-proton (Na+/H+) antiport, crucial for salt tolerance.
Area of Science:
- Plant Physiology
- Molecular Biology
- Biochemistry
Background:
- Salt stress significantly limits plant growth, with tolerance varying by species.
- Salt-tolerant plants utilize vacuolar sodium compartmentalization for survival.
- The tonoplast Na+/H+ antiport is key for sequestering sodium into the vacuole.
Purpose of the Study:
- To investigate the role of a 170 kDa tonoplast polypeptide in the plant vacuolar Na+/H+ antiport activity.
- To identify and characterize the gene encoding the protein associated with the Na+/H+ antiport.
Main Methods:
- Studied sugar beet cell suspensions under varying NaCl concentrations.
- Utilized in vivo labeling of tonoplast proteins.
- Employed polyclonal antibodies against the 170 kDa polypeptide to inhibit antiport activity.
- Screened a Beta lambda ZAP expression library with antibodies.
Main Results:
- Increased NaCl concentrations enhanced vacuolar Na+/H+ antiport activity and 170 kDa polypeptide synthesis.
- Amiloride exposure also increased antiport activity and polypeptide synthesis.
- Antibodies against the 170 kDa protein inhibited antiport activity, suggesting its association.
- A partial cDNA clone encoding a polypeptide with a transmembrane domain was isolated.
Conclusions:
- The 170 kDa tonoplast polypeptide is strongly associated with the plant vacuolar Na+/H+ antiport.
- This protein plays a critical role in mediating sodium tolerance in plants.
- The isolated cDNA clone provides a starting point for further functional and genetic studies.