The Role of Plasma Membrane H+-ATPase in Salinity Stress of Plants

Plants have always been exposed to various stress factors in wild conditions. A high concentration of salt in the soil, i.e., salt stress, is one of the stressogenic stimuli. Salt stress is a complex abiotic stress in which both ionic and osmotic components are involved. Most plants adapted to salinity maintain a relatively low concentration of Na+ in the cytosol achieved through the active exclusion of sodium ions in the apoplast and vacuole. Removal of sodium ions out of the cell, catalyzed by the specific plasma membrane Na+/H+ antiporter, depends on the electrochemical membrane proton gradient. The only pump which generates an electrochemical proton gradient across the plasma membrane is H+-ATPase. For this reason, it is believed that plant plasma membrane H+-ATPase (PM H+-ATPase) plays a major role in salt stress tolerance.