ABSTRACT
Microbes have good capacity to produce a wide range of enzymes that can break down all compounds of plant origin. Microorganisms also play a key role in the cycle of elements. Nitrogen fixation and the mineralization of nitrogen, phosphorus, potassium and sulphur occur under the direct influence of these microorganisms. Fungi break down by increasing their contact area, producing phosphatase enzymes and low molecular weight organic acids such as oxalates. Rhizobacteria affect plant growth, productivity and health through various mechanisms, including dissolution and the enhancement of nutrient bioavailability, the stimulation of root growth and the control of root diseases. Growth-promoting bacteria were isolated from the roots of different plants. After purification and identification, they were used as biogenic fertilizers. The ability of this group of growth-promoting bacteria to increase plant growth has led to their increasing use and they are expected to replace some chemical fertilizers in the future. These bacteria improve plant performance through root system development mechanisms, increasing nutrient uptake and the biological control of plant pathogens, and reducing adverse effects caused by environmental stresses directly or indirectly through the production of IAA, cytokinin, gibberellin, ACC-deaminase and secondary metabolites systems.
