Leveraging microorganisms and biostimulants: mitigating salinity stress in crops with agricultural biologicals

Abstract

Background and Aims: Soil salinity is an increasing threat to crop production and, as a consequence, improving the level of salinity tolerance has become a priority in plant research. Biologicals, including microorganisms and biostimulants, can play a significant role in enhancing plant tolerance to salinity stress, which is further fueled by soil degradation and climate change. Methods: This review explores the mechanisms by which these agents contribute to salinity tolerance. Results: Microorganisms such as plant growth-promoting rhizobacteria, mycorrhizal or endophytic fungi improve plant resilience by facilitating nutrient uptake, producing phytohormones, and enhancing antioxidant activities. They alter root architecture and exude signals that improve water use efficiency, allowing plants to better manage osmotic stress. Biostimulants, comprising amino acids, humic substances, plant and seaweed extracts, further bolster plant tolerance by regulating ion balance and stimulating metabolic pathways associated with the stress response. Some of these substances enhance photosynthetic efficiency, thus maintaining plant growth and productivity under saline conditions. Collectively, the synergistic interaction of microorganisms and biostimulants cultivates a robust soil-plant interface, providing a sustainable strategy to mitigate the impacts of salinity. Conclusion: Continued research is needed to optimize their application methods and to understand the complex interactions within specific crop and soil systems, enabling agricultural systems to adapt to increasing soil salinity levels.