Research Progress of Ca2+-ATPase Involved in Regulation of Plant Salt Tolerance
When cytosolic Ca2+concentration is increased under salt stress,cells would activate Ca2+-regulated target enzymes or induce Ca2+bind to Ca2+high-affinity receptor proteins.Among them,plant Ca2+-ATPases are P-type ATPases,including endoplasmic reticulum Ca2+-ATPase(ECAs)and plasma membrane Ca2+-ATPase(ACAs);they are able to translocate Ca2+from the cytosol to apoplast or compartmentalize Ca2+in organelles.Numerous studies have shown that salt tolerance of plants is largely related to their ability to maintain the activities of calcium pump,namely Ca2+-ATPases.The activities of Ca2+-ATPases in various plant species were sensitive to salt stress;exogenous Ca2+application can alleviate cell injury by salt stress,suggesting that exogenous calcium-mediated Ca2+-ATPase might play an important role in intracellular calcium homeostasis and signal transduction.Therefore,this review summarized the types,structures and properties of plant Ca2+-ATPase,and the involvement of Ca2+-ATPase of subcellular localization in plant response to salt tolerance and the research progress of exogenous calcium and Ca2+-ATPase in regulation on plant salt tolerance.It emphasized potential roles of Ca2+-ATPases of plant plasma membrane,tonoplast,nuclear membrane,endoplasmic reticulum and Golgi in regulation of salt tolerance in plants,and presented an outlook in the field.This work provided help for a better understanding of physiological and molecular mechanisms of plant salt tolerance and provided new ideas for crop salt-tolerance cultivation.