Salinity Stress Resilience in Sorghum bicolor through Pseudomonas-Mediated Modulation of Growth, Antioxidant System, and Eco-Physiological Adaptations.

Abstract

Increased soluble salts in soil and irrigation water threaten the sustainability of crops. This causes food insecurity directly by reducing the staple crop yield and indirectly by limiting fodder and forage production. Recently, plant-growth-promoting rhizosphere microorganism utilization improved crop productivity under stress. Therefore, this research was conducted to find the Sorghum bicolor growth improvement potential by exogenous application of five different Pseudomonas strains under salinity in a pot experiment. The salinity was applied with a 1/2-strength Hoagland's nutrient solution as 0 and 100 mM NaCl for 30 days. Results indicated that salinity reduced the vegetative growth parameters and stress-responsive biochemicals in nonbacterial treated plants. However, Pseudomonas strains applied to plants exhibited notable increases in growth, relative water content, antioxidant enzyme activities, osmolytes, and photosynthetic pigments under salinity. The ionic imbalance was also reduced due to Pseudomonas strains by improving K⁺ and K⁺/Na⁺ ratios under salinity. P. aeruginosa strain SAHK (OQ194056) and P. putida strain AHK_SHA007 (OR468335) were found to be promising compared to other strains in increasing growth and stress tolerance. The augmentation of the plant's antioxidant system and maintenance of ion homeostasis by Pseudomonas strains served as a strategy to enhance the plant salt tolerance.