Rhizobium leguminosarum Mediated Enhancement of Antioxidant Defense in Drought-Stressed Canola: Implication for Agriculture and Pharmaceutical Research

Abstract

One of the most critical environmental factors that negatively impact the growth, yield and nutrient status of canola is drought stress caused by nutrient deficiency and oxidative damage. In the present study, the effect of Rhizobium leguminosarum on antioxidant defense mechanism and nutrient status of drought stressed canola plants was highlighted. The activity of important antioxidant enzymes like Superoxide Dismutase (SOD), Catalase (CAT) and Peroxidase (POD) was also found to be significantly improved by R. leguminosarum inoculation which effectively scavenged the Reactive Oxygen Species (ROS) produced in water-deficit condition. Stress tolerance of plants was enhanced by reducing the amount of lipid peroxidation and plant damage caused by the increased antioxidant protection. Furthermore, the bacterial inoculation helped to ensure the uptake and retention of different nutrients (N, P, K, Ca and Mg), and thus improved the physiological performance and metabolic stability under drought stresses. Overall, these two benefits of combined antioxidant and nutrient uptake resulted in improved growth, biomass production and water stress tolerance in plants. Based on the results, use of R. leguminosarum as bioinoculant could be a sustainable strategy to enhance the productivity of canola crops under drought stress. Furthermore, the greater level of anti-oxidants and nutritional characteristics has the potential to enhance the pharmaceutical and nutraceutical applications of canola products in the health industry.