Abstract
Plant growth-promoting bacteria (PGPB) are microorganisms capable of enhancing plant growth through various mechanisms, including rhizosphere bacteria, endophytic bacteria, and certain fungal organisms. This paper systematically summarizes the main functions and mechanisms of PGPB, encompassing the synthesis of plant growth regulators (such as auxins, cytokinins, and gibberellins), nitrogen fixation, activation of nutrients like phosphorus and potassium, mitigation of abiotic stresses (e.g., drought and salinity), and defense against biotic stresses (e.g., pathogenic infections). Additionally, it highlights the critical roles of PGPB in regulating plant root system architecture and shaping the rhizosphere microbial community. On the application side, this paper reviews the screening and preparation technologies of PGPB, including strain selection, carrier development, and preservation techniques, along with diverse inoculation methods such as seed coating, soil application, foliar spraying, and root drenching. The multifunctionality and potential of PGPB in microbial inoculants, agricultural biopesticides, and biofertilizers are discussed through typical application cases, emphasizing their pivotal role in promoting sustainable agriculture. This study provides theoretical support for understanding the functional mechanisms of PGPB and their applications in addressing climate change, improving agricultural productivity, and enhancing resource use efficiency. It also outlines future research and practical directions in this field.
