An overview of bacterial bio-fertilizers function on soil fertility under abiotic stresses

Agricultural operations are moving towards more environmentally friendly and sustainable methods because the excessive use of chemical fertilizers and pesticides in farmlands endangers human health and the environment. Rhizobacteria stimulate the growth of plants through various mechanisms (e.g., enhancement of the bioavailability of nutrients, stimulating root growth, and controlling root diseases). The main goal of developing biotechnology for plant growth-promoting bacteria is to increase the population of bacteria that benefit the soil, which can help with the development of sustainable agriculture that reduces the need for chemical fertilizers and pesticides. Bacteria have a beneficial effect on plant growth by providing the plant with their required nutrients, producing antibiotics, increasing the production of plant growth factors, and preventing root diseases. The bacteria that are on the list of growth-promoting bacteria include Flavobacterium, Arthrobacter, Bacillus, Enterobacter, Azotobacter, Azospirillum, and Pseudomonas. The process of molecular nitrogen fixation performs in three general modes: Free-living, Symbiosis coexistence, and Associative symbiosis. The rhizosphere bacteria and the host plant link are extra-root and endophytic. Beneficial extra-root bacteria are defined by the following three inherent characteristics: the ability to colonize the root, be able to survive and grow and multiply in the micro-locations of the root surface to compete with other microorganisms, and be prepared to show growth-stimulating activities and increase plant growth.