Morphological and Molecular responses in plants to Salinity: An Overview

Abstract

In the soils of arid and semiarid areas, salt stress is a serious threat which constitutes nearly 40% of the earth’s land area. Salinity is the amount of dissolved mineral salts like the electrolytes of positive ions like Na+, Ca2+, Mg2+ and K+ and negative ions like Cl-, SO42-, HCO3 -, CO32- and NO3- present in soil and ground. Salinity stress causes the generation of reactive oxygen species that limits the metabolism and destroys DNA, proteins, lipids and other macromolecules of the cell through oxidation. Under the influence of salinity, plants should fight against two main stresses: - (i) osmotic stress and (ii) ionic stress. In plants, balancing of ions is crucial due to high concentration of salt. Furthermore, the salt stress impacts on the inhibition of biochemical and physiological processes, whole plant growth through osmotic effects, particular ion toxicity, nutritional imbalances and disturbance in the hormonal homeostasis. To survive in saline environments, plants rely on a variety of stress-responsive proteins. These proteins include ion transporters that help maintain ionic balance. Proteins, dehydrins and proline biosynthetic enzymes support osmotic adjustment, while antioxidant enzymes protect against oxidative damage. Signal transduction proteins and transcription factors regulate stress-responsive genes, while aquaporins and heat shock proteins maintain water flow and protein stability. Traditional breeding methods have limited success in developing salt-tolerant crops due to the complex genetic basis of stress responses. In recent years, genome editing tools have emerged as a powerful alternative for precise genetic improvements in plants. Among these tools, the CRISPR-Cas system has gained prominence due to its simplicity, accuracy and versatility.