Beneficial traits of crop-associated rhizobacteria toward plant growth promotion, biofertilization, and nutrient enhancement of harvested agro-products

Considering the global demand for food crops and the adverse effects of the indiscriminate use of agrochemicals in current agriculture, the use of rhizospheric bacterial strains as biofertilizers emerges as a promising strategy to produce food crops in a sustainable manner. A variety of rhizobacterial microorganisms have desirable characteristics that can foster plant growth and nutrient enhancement in the harvested agro-products. Different biofertilization mechanisms are used by microorganisms in their interaction with the plant, such as mineral solubilization, the production of phytohormones and siderophores, and other secondary metabolites and enzymes. On the other hand, through the synthesis of organic compounds, beneficial rhizobacteria can not only favor the growth of the plant but also exert a protective activity against pathogens (biocontrol) and induce the plant’s resistance toward abiotic factors that affect its development. Furthermore, there is a growing interest in researching the impact of biofertilization on crop growth and yield, as well as nutritional quality and the production of bioactive compounds in harvested products. This review emphasizes the relevance of rhizobacteria used as biofertilizers in crop development and productivity, considering the effect of the bacterial inoculants on the alteration of the rhizosphere microbiome’s composition and diversity, the biofertilization mechanisms, and the induction of the plant’s resistance to biotic and abiotic stresses. The emphasis of this review was directed toward in vivo studies focusing on seedlings, plants, and final crop products that attest to the applicability of crop biofertilization as a sustainable alternative to face the current global agricultural challenges.