Probiotic assisted drought tolerance in green gram: A novel strategy for sustainable agriculture

Drought stress is a critical factor that limits crop growth and yield. Biopriming has emerged as an effective and eco-friendly method to mitigate drought stress and enhance plant growth. This study evaluated the impact of nodule-associated plant probiotics (NAPP) on green gram seeds through treatments such as biopriming, coating and their combination of biopriming + coating along with hydropriming and uninoculated seeds served as a control in both in vivo and pot experiments. The study demonstrated that a combination of 6 mL biopriming + 4 mL coated seeds significantly improved the speed of germination (33%), germination percentage (16%), total seedling length (31%), dry weight (29%), seed vigor index (50%) compared uninoculated seeds. In the pot experiment, seeds treated with the combination of biopriming + coating were planted in different drought conditions viz., severe drought (40% water holding capacity, WHC), moderate drought (70% WHC) and controlled conditions (100% WHC). Combining biopriming + coated seeds showed a higher photosynthetic rate and relative water content, significantly improving plant growth under drought stress and optimal conditions. The biochemical study found that combining biopriming + coated seeds considerably increased proline content, total soluble protein and antioxidant enzymes under drought stress and control conditions. Furthermore, the combination significantly increased yield components, including the number of seeds, pods, 100-seed weight and root nodules, under both control and drought stress conditions. Principal component analysis (PCA) confirmed the modulation of growth, root nodules, antioxidant enzymes and yield components by combining biopriming and coating. It also showed reduced electrical leakage (EL) in green gram under drought stress conditions.