Salinity tolerance mechanisms in rice: A review

Rice (Oryza sativa L.) is one of the most important cereal crop globally and it is the staple food of more than half of world population. Current average yield is 10 to 15% lower than its potential yield. There are many reasons for this yield gap such as biotic and abiotic stresses, management strategies as well as nutrient deficiencies. Salinity is one of the most serious factors limiting the productivity of rice, with adverse effects on germination, plant vigor and crop yield. This salinity may be natural or induced by agricultural activities such as irrigation or the use of certain types of fertilizer.Salinity induced ionic imbalance and osmotic stress affect water and nutrient uptake, stomatal closure, gas exchange, photosynthesis, transpiration, carbon assimilation and hence decrease in rice yield. Studying the response of rice at physiological, genetic and molecular level is the mandate to develop salt tolerant rice varieties. This review described the impact of salt stress in rice, various types of salt tolerance mechanisms in rice, including the ion homeostasis, production of compatible organic solutes, antioxidative genes, salt responsive regulatory elements, role of ion transporters and channel proteins. Further, the future perspective of developing salt-tolerant varieties using landraces via., marker assisted breeding, genome editing tool, utilization of beneficial microorganisms.