Plant growth-promoting bacteria (PGPB) play a crucial role in helping plants withstand abiotic stresses by direct (including biological nitrogen fixation, siderophore production, and nutrient solubilisation) and indirect mechanisms (inducing systemic resistance and activating plant's defense responses). These beneficial microbes modulate various physiological and biochemical processes thereby enhancing the plant's antioxidant defense system, regulate stomatal behavior, promote root development, and improve photosynthetic efficiency by stabilizing chlorophyll content and photosynthetic protein complexes. A key function of PGPB is the activation of internal antioxidant mechanisms that mitigate the damaging effects of reactive oxygen species (ROS) produced under stress conditions. Emerging research has begun to explore the involvement of rhizobacterial phytohormones in PGPB-mediated stress priming, although the exact roles and mechanisms remain to be fully elucidated. Many studies have focused on rhizobacterial strains isolated from plants already adapted to harsh environments, suggesting these microbes possess intrinsic adaptations that support plant resilience against anthropogenic stressors. Inoculation with such stress-adapted PGPB strains has shown potential to enhance plant growth and yield under adverse conditions. This review highlights the multifaceted interactions among PGPB, plants, soil, and abiotic stress factors (including drought, salinity, extreme temperature and heavy metals), emphasizing their collective impact on plant stress tolerance. Understanding these complex relationships is essential for developing sustainable strategies to improve crop performance in stress-prone environments.
Rani et al. (Wed,) studied this question.