Plant growth-promoting bacteria and exogenous phytohormones alleviate the adverse effects of drought stress in pigeon pea plants

AimsThis study aims to alleviate the adverse effect of water stress on pigeon pea plants using rhizospheric bacteria and exogenous application of indole acetic acid and gibberellic acid.MethodsTwo root-associated bacteria were isolated from Suaeda nudiflora wild mosque plant, identified molecularly using 16 S rDNA analysis, and recognized as Pseudomonas aeruginosa and Bacillus megaterium.ResultsThe results revealed that drought stress caused a significant decrease in morphological traits, photosynthetic pigments, stomatal conductance, net photosynthetic rate, hill reaction, relative water content, membrane stability index, total soluble protein, endogenous phytohormones, and mineral content as compared to non-stressed plants. In contrast, drought stress caused a significant increase in intracellular CO2 concentration, total soluble sugars, total free amino acids, lignin, lignin monomer, and abscisic acid in pigeon pea plants. The application of plant growth promoting bacteria (PGPB) (P. aeruginosa and B. megaterium) in combination and treatment with exogenous phytohormones positively affect morphological and physiological characters. In the in-silico study of the molecular interaction of indole acetic acid and gibberellic acid with enzyme hydrolase, only inaction with indole acetic acid was shown and indicates the presence of many sites for polar interaction, an important indicator for drought stress.ConclusionIn conclusion, treating bacterial isolates and exogenous hormones helps mitigate the harmful effects of drought by enhancing osmolytes production, increasing photosynthetic activity, and increasing mineral uptake, causing an increase in plant growth and improving sustainable agriculture.