Targeting vacuolar sodium sequestration in plant breeding for salinity tolerance

Salinity is a major environmental issue affecting crop production around the globe, and creating a salt-tolerant germplasm is absolutely essential meeting the 2050 challenge of feeding a 9.3 billion population. While most efforts of plant breeders were focused around genes and mechanisms responsible for exclusion of cytotoxic Na⁺ from uptake, this is not the strategy naturally salt-tolerant halophyte species use. One of the hallmarks of halophytes is their ability to safely deposit large volumes of salt in their vacuoles, in the process termed vacuolar sodium sequestration. This chapter reviews molecular and physiological mechanisms mediating this process and prospects of their targeting in breeding programs.