The role of endophytic bacteria in enhancing plant growth and health for sustainable agriculture

Given the impact of abiotic and biotic factors on agriculture, it is crucial to adopt sustainable and environmentally friendly practices to enhance yields. One approach that is gaining prominence is the utilization of plant-growth-promoting bacteria (PGPB) in mainstream agriculture. Interactions between plants and microbes in the rhizosphere play a vital role in plant health, productivity, and soil fertility. PGPB, particularly endophytes that establish close associations with plants, have shown success in promoting plant growth and protecting plants against diseases and abiotic stresses through various mechanisms, including biological nitrogen fixation, phosphate solubilization, siderophore production, phytohormone production, ACC-deaminase activity, induced systemic resistance, quorum sensing, hydrogen cyanide synthesis, hydrolytic enzyme and colonization niche specialization. While there is no one-size-fits-all strategy for promoting the growth of every plant under every condition, certain strategies discussed in this review already demonstrate significant promise. This review provides an overview of the current understanding of the fundamental mechanisms employed by PGPB, and emphasizes innovative methods for identifying and developing promising strains to serve as bio-inputs. Likewise, the aim of this review is to present a summary of the crucial role that soil-plant-microorganisms interactions play in the development of efficient bioinoculants, as well as to explore biotechnological advances. Bacteria from genera such as Azospirillum, Bacillus, Bradyrhizobium, and Pseudomonas have already been widely studied and applied for these purposes. However, further research is needed to improve strain performance and enhance the potential of multifunctional microorganisms. Deepening the genetic and biochemical understanding of these mechanisms and expanding their applications is essential to foster safe and sustainable agronomic practices.