Enhancing plant resilience and drought stress in green gram through seed priming with nodule-associated plant probiotics

Drought stress is a critical environmental stress that hinders plant growth and development. Most pulses are grown in rainfed ecosystems, significantly affected during drought conditions. To address this predicament in this study, a liquid microbial consortium of nodule- associated plant probiotics was used for seed priming of Greengram to assess its efficacy in alleviating drought stress and improving seed quality attributes. Applying an optimum dose of plant probiotics at the appropriate stage enhances plant productivity, improving tolerance to stresses and reducing dependence on harmful agrochemicals. To optimize the dose, two green gram seeds viz., VBN4 and CO8, were subjected to various concentrations of nodule-associated plant probiotics (NAPP), namely, 2, 4, 6 and 8%, along with the control and hydropriming. In the present study, 2% NAPP improved the physiological and biochemical parameters of the green gram, such as germination, seed vigour index, protein content, dehydrogenase activity and alpha- amylase in both varieties. The primed seeds were further evaluated under moisture stress conditions by exposing them to various concentration levels of Polyethylene Glycol 6000 ranging from-2 to-6 bar. The experiment revealed that increasing the concentration of PEG 6000 above in-4 bar reduced germination and seedling vigour in both green gram varieties. However, green gram seeds primed with 2% NAPP showed greater moisture stress resistance than nonprimed seeds. The highest activity of stress-related enzymes such as catalase, peroxidase and super oxidase dismutase triggered by NAPP in green gram plants was observed to have potential for drought stress management. This study highlights the importance of NAPP as a potential seed priming agent for improving seed germination and vigour under moisture stress.