The soil rhizosphere is teeming with diverse microorganisms, including fungi, bacteria, protozoa, and algae. Among them, bacteria are the most abundant and can be either plant pathogenic or beneficial. Plant Growth Promoting Rhizobacteria (PGPR) are the microbes that occur naturally, free-living in nature that exist in the soil and are important for promoting plant growth. PGPR are beneficial microorganisms that reside in rhizosphere and significantly contribute to plant growth and productivity. These bacteria employ a diverse array of mechanisms to promote plant growth, which can be broadly categorized into direct and indirect mechanisms. Direct mechanisms include nitrogen fixation, phytohormone production and phosphate solubilization which collectively improve plant nutrient uptake and physiological functions. Indirect mechanisms involve the suppression of phytopathogens through the production of antimicrobial compounds, competition for resources and induction of systemic resistance in plants. This review explores the multifaceted mechanisms employed by PGPR, emphasizing their role in sustainable agriculture

Rhizosphere, Plant Growth Promoting Rhizobacteria (PGPR), direct nitrogen fixation, phosphate solubilization, HCN production, Competition

Plant growth-promoting rhizobacteria (PGPR) contribute significantly to increasing plant production and growth through a variety of direct and indirect ways. By facilitating synthesization of growth-promoting phytohormones and inducing systemic resistance, PGPR contribute significantly to plant health and resilience. Advancements in molecular and genomic technologies have deepened our understanding of PGPR functionality, enabling the development of targeted bioinoculants and tailored agricultural practices. However, harnessing their full potential requires further research into strain-specific effects, plant-microbe interactions, and field-level performance under diverse environmental conditions. We can create resilient, resource-efficient, and environmentally friendly crop production methods that satisfy the needs of a growing world population by incorporating PGPR into agricultural systems

S.A. Rathod, D.S. Rabari and S.S. Kansara (2025). Plant Growth Promoting Rhizobacteria: Mechanisms and Their Role in Sustainable Agriculture. Biological Forum – An International Journal, 17(1): 90-94