Deciphering the mechanism of action and crosstalk of brassinosteroids with other plant growth regulators in orchestrating physio-biochemical responses in plants under salt stress

Abiotic stresses severely impact crop plant growth, physio-biochemical functions, and productivity leading to significant crop losses across the globe. Among abiotic stresses, salt stress is a major environmental constraint that severely affects crop productivity. The elevated levels of salt stress induce the production of harmful reactive oxygen species (ROS) that cause ionic toxicity and osmotic stress which disturbs the hormonal balance, denatures proteins, damages enzyme structure and imbalances cellular ion homeostasis and metabolic pathway, all contribute to poor plant growth, in severe cases, plant death. However, researchers are actively exploring strategies to mitigate salt stress effects and improve crop production. Of various, one effective approach is the exogenous application of plant growth regulators (PGRs), which can counter the adverse effects of salinity and enhance crop growth and productivity. Among PGRs, brassinosteroids (BRs) stand out as an emerging signaling molecule that regulates various plant processes, including cell division, elongation and differentiation, as well as morphogenesis, seed germination, flowering, and fruit development. It also enhances plant resistance to various stresses by modulating gene expression and signaling pathways. Studies revealed that exogenous BRs application has shown promising results in modulating morphological traits, photosynthetic efficiency, and enzymatic activities by enhancing antioxidant defenses and osmolyte accumulation, thus improving plant tolerance to salt stress. The present review article aims to provide valuable insights into the crosstalk between BRs and other PGRs in enhancing plant salt stress tolerance. This article also discusses BRs biosynthesis and mechanism of action and provides a comprehensive review of literature on BRs role in regulating plant growth, development, and yield under salt stress conditions.