Strategies of NHX antiporters to deal with salt stress

The adverse effects of salinity on plant growth are generally associated with the low osmotic potential of the soil solution and the high level of sodium toxicity (and chlorine toxicity for some species) which cause multiple perturbations on plant metabolism, growth, and development at the molecular, biochemical and physiological levels. The vacuolar NHX and plasma membrane SOS antiporters mediate cation and proton exchange across the tonoplast and plasma membrane, respectively. The SOS transporters allow the excretion of Na+ from the cytoplasm to the outside environment and alternatively, NHXs provide Na+ transport from the cytoplasm to the vacuole. Cellular ion homeostasis is an essential phenomenon for all organisms. Most cells manage to maintain a high level of potassium and a low level of sodium in the cytoplasm through the coordination and regulation of different transporters and channels instead of the NHX-type vacuolar antiport. In this article, some important mechanisms in the regulation of ionic ions such as Na+. will be discussed.