Plant growth promoting rhizobacteria and nanotechnology: emerging perspectives and functional roles for climate resilient sustainable agriculture.

This review highlights the pivotal role of Plant Growth Promoting Rhizobacteria (PGPR) in association with nanotechnology for enhancing plant growth and health. It narratively discusses diverse PGPR groups and genera, outlining their direct mechanisms such as phosphate solubilization, nitrogen fixation, ACC deaminase activity, hydrogen cyanide production, and siderophore production for iron chelation as well as indirect mechanisms through induced systemic resistance (ISR) and systemic acquired resistance (SAR). The application of PGPR as single inoculants and in consortia, together with omics-based approaches, is examined to demonstrate their versatility in sustainable crop improvement. PGPR interactions with host plants, contributions to soil protection, and conditioning are also addressed. Despite their multifaceted benefits, limitations such as loss during aerial application or environmental stress remain challenges. Emerging nanotechnology-based delivery systems offer promising solutions by enabling controlled release of PGPR and their bioactive compounds, thereby targeting specific tissues and enhancing resilience under variable conditions. Collectively, this review underscores PGPR- mediated green nanotechnological strategies as eco- friendly alternatives to hazardous chemical inputs, advancing climate-resilient and sustainable agriculture.