Gene regulation in halophytes in conferring salt tolerance

Abstract

Abstract Salinity is one of the significant stresses that affect all the metabolic and physiological aspects of all the plants, and on this consistency, some genes are upregulated, and some are downregulated to confer salt stress. In this aspect, halophytes are enriched with all the essential machinery to overcome salt stress by switching genetic pathways that inhibits the entry of toxic ions (Na+ ions and Cl− ions), or by compartmentalization of these ions in subcellular organelles, which not only protect the plants at germination stage but also provide protecting shield at growth and developmental level. Na+ flux entered from roots to leaves, and it enters at cellular level accomplished via KUP/HAK/KT, KT, HKT1, AKTI, and NSCCs (nonspecific cation channels) transporters. Available literature indicates that at germination stage, Cdc2-related protein, Vp1 and MIP proteins (proteins of aquaporins) related to transcripts, and DOG1, AB15, and RGL2 genes are upregulated in halophytes. Besides, at developmental stages glycine-rich RNA-binding proteins (SvGRP1 and SvGRP2), APX (ascorbate peroxidase) gene, TsApx6 is switched on to overcome salinity stress. In this content, cytoplasmic damage is controlled by the upregulation of genes involved in ionic compartmentalization such as NHX, CLC, and AQP. Furthermore, SOS, HA1, NHX, VAMP, CLC, PIP, SOS1, PIP (aquaporin involved in salt secretion), and TIP genes are upregulated for salt secretion; a specific attribute is only related to halophytes. Moreover, for intragenic recycling roots hydrophobic barriers genes cytochrome P450 (involved in the hydrophobic root barrier) SOS1 and AoCYP86B1 are switched on. The damaging effect of salt can be at least, and partially reversed by the expression of these genes in glycophytes and other halophytes. These findings have enormous implications for growing halophytes and glycophytes in the areas where salinity is a major limiting factor for plant growth and development.