Use of plant growth-promoting bacteria to stimulate the growth and development of rice ( O . sativa L.) and bean ( P . vulgaris L.) cultivars

Current fertilization practices are unsustainable from both an environmental and a human health perspective. A promising solution has emerged in plant growth-promoting bacteria (PGPB), which can act hand in hand with synthetic fertilizers to reduce their environmental costs. This study seeks to isolate, characterize, and evaluate the ability of nitrogen-fixing bacteria (NFB) as a potential biofertilizer of important crops, such as bean and rice cultivars. 18 NFB strains were isolated from the rhizosphere of beans, lentils, and rice plants, with a few isolated from nodules or topsoil. To identify elite strains, primary growth-promoting mechanisms were determined, including mineral solubilization, N2-fixation ability, and production and secretion of indole-3-acetic acid (IAA). Of the 18 initial isolates, BN03, BN09, BN16 and BN18 showed the greatest potential as biofertilizers. These isolates were used individually and in consortium as bioinoculants for bean and rice plants in pot experiments, showing significant improvements in every biometric parameter measured. These results join others in showcasing the potential of beneficial microorganisms to promote the development and growth of important crops in the transition to sustainable agriculture.