Crosstalk between Ca and Other Regulators Assists Plants in Responding to Abiotic Stress.

Plants have evolved many strategies for adaptation to extreme environments. Ca, acting as an important secondary messenger in plant cells, is a signaling molecule involved in plants' response and adaptation to external stress. In plant cells, almost all kinds of abiotic stresses are able to raise cytosolic Ca levels, and the spatiotemporal distribution of this molecule in distant cells suggests that Ca may be a universal signal regulating different kinds of abiotic stress. Ca is used to sense and transduce various stress signals through its downstream calcium-binding proteins, thereby inducing a series of biochemical reactions to adapt to or resist various stresses. This review summarizes the roles and molecular mechanisms of cytosolic Ca in response to abiotic stresses such as drought, high salinity, ultraviolet light, heavy metals, waterlogging, extreme temperature and wounding. Furthermore, we focused on the crosstalk between Ca and other signaling molecules in plants suffering from extreme environmental stress.