Sustainable agricultural practices and environmental friendly technologies are need of the hour with the increasing pollution, soil degradation, high food demand, over-application of chemical fertilizers, and exacerbating climate change. These management practices will improve the resource use efficiency and certainly help in the mitigation of stated challenges. One of such promising approach is the utilization of plant growth-promoting rhizobacteria (PGPR). PGPR inoculants are a promising strategy to mitigate biotic and abiotic stressors in agricultural areas, thereby increasing global food production. The use of PGPR enhances the plant growth, initiates plant defense mechanism against pathogens, and also aids in the process of bioremediation. PGPR offers a plethora of benefits to the plant and environment and can be a sustainable alternative to conventional agrochemicals and traditional farming. Studying plant relationships and microbiomes is crucial for strengthening traditional techniques and incorporating new management strategies. This chapter aims to enhance understanding of convergence mechanisms and ambiguities in signaling activities in the host due to interactions with PGPR in demanding environmental situations. It covers the role of PGPR in defense related mechanism such as production of antimicrobial compounds, volatile compounds, induced systemic resistance (ISR), modulation of plant hormones, immune response to different abiotic stresses including salinity, temperature, heavy metal and drought stress. The study underscores the necessity of ongoing research and implementation of PGPR-based strategies to tackle global food security challenges, including commercialization of sustainable agricultural bio-formulations.