Abstract
Abstract Microbial biostimulants (MBs) are gaining recognition as an essential component of sustainable agriculture due to their ability to enhance crop productivity, improve resilience to abiotic and biotic stresses, and reduce dependence on synthetic agricultural inputs. As global agricultural systems face increasing challenges from climate change and environmental degradation, MBs offer an environmentally sustainable strategy to improve plant performance and maintain long-term soil health. This review provides a comprehensive overview of recent advances in the development and application of MBs, with particular emphasis on plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF). Their mechanisms of action are comprehensively reviewed, including their roles in enhancing nutrient acquisition, stimulating plant growth, and improving tolerance to environmental stresses. The synergistic effects of PGPR–AMF consortia in improving crop productivity and quality under adverse environmental conditions are also discussed. In addition, the review evaluates the direct and indirect mechanisms through which MBs mitigate drought, salinity, nutrient deficiency, and pathogen pressure. Current challenges, including limited mechanistic understanding, inconsistent field performance, and formulation standardization, are critically discussed. To maximize the potential of MBs, future research should focus on elucidating plant–microbe interactions using advanced multi-omics approaches, optimizing microbial consortia and formulations, and validating their efficacy through long-term, multi-location field trials. These advances will facilitate the wider adoption of MBs for improving soil health, enhancing food security, and supporting climate-resilient and resource-efficient agricultural systems. Graphical abstract