Role of Plant Growth-Promoting Rhizobacteria in Enhancing Crop Productivity

Abstract

Plant growth-promoting rhizobacteria (PGPR) offer an environmentally sustainable approach for improving crop productivity by enhancing nutrient availability, root development, biological stress tolerance and soil microbial balance. This paper examines the role of beneficial rhizobacteria in promoting crop growth through a literature-based review of direct and indirect mechanisms, including biological nitrogen fixation, phosphate solubilisation, siderophore production, indole-3-acetic acid production, 1-aminocyclopropane-1-carboxylate deaminase activity, induced systemic resistance and antagonism against phytopathogens. The discussion shows that PGPR can improve germination, root proliferation, nutrient uptake, chlorophyll formation, biomass accumulation and yield-related traits, particularly when inoculants are well matched to crop species, soil conditions and management systems. However, the paper also finds that field performance is less predictable than laboratory performance because survival, rhizosphere colonisation, formulation quality, soil chemistry, drought, salinity, temperature and competition with native microbiota can reduce inoculant effectiveness. The findings support the use of PGPR as biofertilisers and biostimulants in sustainable agriculture, but they also indicate that PGPR should complement, rather than automatically replace, fertiliser and crop-protection strategies. Overall, microbial-based interventions can contribute to resource-efficient crop production, soil health and environmentally responsible farming when they are supported by rigorous strain screening, field validation and farmer-oriented application protocols.