An investigation on the role of salicylic acid alleviate the saline stress in rice crop (Oryza sativa (L))

Among the different naturally occurring plant hormones Salicylic Acid (SA) is one of the important signal molecules. The current study was carried out to investigate whether foliar spray of SA could improve the different parameters and help to alleviate the saline stress in rice seedlings. Saline stress (100 mM NaCl) significantly reduced the photosynthetic and total protein content. Increased NaCl concentration exhibited a significant increase in antioxidant enzymes activity. Plants grown under high saline stress showed more accumulation of ROS with DAB staining and exhibited the fragmented nuclei by DAPI staining. Foliar spray of SA showed the improved photosynthetic and protein content, reduced antioxidant enzymes activity, lower accumulation of ROS and intact nuclei. Further, expression of Catalase-1 (CAT-1), Superoxide dismutase (SOD) and Glutathione Peroxidase (GPX) genes showed upregulation during NaCl treatment and coincide with antioxidant enzymes activities. Expression of Mitogen activated protein kinases-1 (MAPK-1), transcription factor WRKY53, Box Inhibiotr-1 (BI-1), and nine Autophagy Related Genes (ATGs) were showed upregulation during NaCl treatment. Foliar spray of SA induced the expression of different genes in control and NaCl treated rice seedlings and suggested that SA helpful to alleviate the saline stress. The study suggested that SA is a potent signaling molecule not only with promotive effect on plants but may also be helpful to reduce the toxic effect of saline stress. Furthermore, study concludes that saline stress is regulated by multiple pathways including SA, MAPK1, Programmed Cell Death (PCD) and autophagy. These pathways may help to cope up with saline stress in rice seedlings.