Can Bacillus Species Enhance Nutrient Availability in Agricultural Soils?

One major challenge for the twenty-first century will be the production of sufficient food for the global human population. The negative impacts on soil–plant–microbes–environmental sustainability due to injudicious use of chemical fertilizer, pesticide, insecticide, etc. by the unaware farmers deteriorate soil and environment quality. One possible way to use efficient soil microorganisms to remediate nutrient deficiency in agricultural soils and other plant growth-promoting (PGP) activities that can be of help for plant growth and development. The Bacillus species is one the most dominant rhizospheric bacterial/rhizobacteria species like Bacillus subtilis, B. cereus, B. thuringiensis, B. pumilus, B. megaterium, etc. that can help enhance the plant growth and development by different mechanisms, which PGPR can inhibit phytopathogens is the production of hydrogen cyanide (HCN) and/or fungal cell wall degrading enzymes, e.g., chitinase and s-1,3-glucanase. Direct plant growth promotion includes symbiotic and non-symbiotic PGPR which function through production of plant hormones such as auxins, cytokinins, gibberellins, ethylene, and abscisic acid. Mitigate the challenge by adopting eco-friendly crop production practices. Some Bacillus species function as a sink for 1-aminocyclopropane-1-carboxylate (ACC), the immediate precursor of ethylene in higher plants, by hydrolyzing it into α-ketobutyrate and ammonia and in this way promote root growth by lowering indigenous ethylene levels in the micro-rhizo environment. Bacillus species also help in solubilization of mineral phosphates, potassium, zinc, and other nutrients; rhizobacteria retain more soil organic N and other nutrients in the soil–plant system, thus reducing the need for fertilizers and enhancing release of the nutrients from indigenous or mineral sources, enhancing the economic and environmental sustainability.