Salt adaptation mechanisms of halophytes: Improvement of salt tolerance in crop plants

Abstract

Soil salinity is one of the most serious environmental factors that affect crop productivity worldwide. Inevitable global climate change leading to rise in sea water level would exacerbate degradation of irrigation systems and contamination of ground water resources, which render conventional agricultural practices impossible due to the sensitivity of most crops to salinity. Breeding for development of salt-tolerant crop plants has been a major challenge due to the complexity and multigenic control of salt tolerance traits. Halophytes are capable of surviving and thriving under salt at concentrations as high as 5 g/L, by maintaining negative water potential. Physiological and molecular studies have suggested that halophytes, unlike glycophytes, have evolved mechanisms, such as ion homeostasis through ion extrusion and compartmentalization, osmotic adjustments, and antioxidant production for adaptation to salinity. Employment of integrated approaches involving different omics tools would amplify our understanding of the biology of stress response networks in the halophytes. Translation of the knowledge and resources generated from halophyte relatives of crop plants through functional genomics will lead to the development of new breeds of crops that are suitable for saline agriculture.