The role of plant cation/proton antiporter gene family in salt tolerance

Salinity is one of the major abiotic constraints to agriculture. The physiological and molecular mechanisms of salt tolerance have been studied in plants for many years. The regulation of osmosis and ion homeostasis is crucial. A lot of important components involved in plant responses to salt stress have been identified. Among them, ion transporters and channels take an essential role in ion homeostasis, mainly for Na⁺, Cl^-, and K⁺. Until now, many cation antiporters important for salt tolerance in plants have been characterized. Among them, the monovalent cation/proton antiporters (CPA) family is one of the most important families, including sodium proton exchangers (NHXs), K⁺-efflux antiporters (KEAs), and cation/H⁺ exchangers (CHXs). Here, the current knowledge of the plant CPA family in responses to salt stress is reviewed. The regulation mechanisms were also included and discussed.