Abstract

Salt tolerant plants have been characterized by their ability to cope with osmotic and ionic stresses caused by elevated sodium chloride (NaCl) concentrations. For homeostatic control of Na⁺, plants have evolved a system of membrane channels and antiporters that facilitate the influx and efflux of sodium (Na⁺) ions at the roots and establish a steady state rate of entry of Na⁺ into the plant, compartmentation of Na⁺ into the cell vacuoles and transfer to various plant tissues. To enhance the salt tolerance of salt sensitive plants, genetic engineering with sodium and hydrogen (Na⁺/H⁺) antiporters is one of the preferred methods in recent years. The aim of this study is to highlight and discuss the recent progress in understanding Na⁺ transport in plants, and genetic engineering of plants with Na⁺/H⁺ antiporters to increase their salt stress tolerance. The present status of salt stress tolerance in transgenic plants was examined and possibilities were recommended that may further enhance salt tolerance if given proper research attention. Moreover, future challenges including environmental risk assessment confronting transgenic plants transformed with Na⁺/H⁺ antiporters were also discussed.

Key words: Salt tolerance, Na⁺/H⁺ antiporters, transgenic plants, vacuolar compartmentalization.