Understanding the Integrated Pathways and Mechanisms of Transporters, Protein Kinases, and Transcription Factors in Plants under Salt Stress

Figure 1

Schematic representation of Na⁺ and K⁺ transporters mediating Na⁺ and K⁺ homeostasis in plant roots under salt stress. Na⁺ ions enter the cells via nonselective cation channels (NSCCs) and possibly via other cation transporters (symplast flow) and intercellular spaces (apoplast flow). The SOS1 extrudes Na⁺ at the root-soil interface and the xylem parenchyma cells. Likewise, HKT also retrieves Na⁺ from the xylem. SOS1, localized in the xylem parenchyma cells, mediate Na⁺ efflux from xylem vessels under high salinity. Excessive Na⁺ in root is sequestered in the large central vacuole by tonoplast-localized NHX exchangers, V-ATPase, and V-PPase which also generate electrochemical potential gradient for secondary active transport.