Root driven hormones and plant growth promoting rhizobacteria as natural biostimulants for sustainable crop growth

Abstract

The growing need for sustainable farming has renewed interest in plant growth-promoting rhizobacteria (PGPR) as eco-friendly alternatives to chemical fertilizers. Beyond their well-known roles in nutrient acquisition and disease suppression, PGPR are now recognized for producing key phytohormones such as auxins, gibberellins, cytokinins, and ethylene modulators that directly shape plant growth and stress responses. This review highlights recent progress in understanding these hormonal interactions and the use of advanced techniques, including high-performance chromatography and mass spectrometry, to isolate and quantify microbial phytohormones with greater accuracy. It also brings attention to the synergistic benefits of combining different PGPR strains, their adaptability to soil environments, and their ability to alleviate heavy metal and pesticide stress. By linking traditional microbiological knowledge with modern analytical and molecular approaches, this work outlines how PGPR can be developed into reliable bioinoculants for future farming systems. The review aims to provide fresh insights into how phytohormone-producing PGPR can be harnessed to enhance productivity while reducing dependence on synthetic inputs.