Brassinosteroids Biology in Plants Under Drought Stress: Physiological and Molecular Aspects

Crop productivity is drastically affected by abiotic stresses, which are major constraints in agricultural development. Drought stress provides severe limitations on agricultural growth, leading to a notable decrease in the production of crops. Drought stress is a significant cause of production losses, and its occurrence is predicted to become more often due to global temperature changes. There are many factors contributing to the loss of productivity caused by drought, including drastic changes in plant physiology. To alleviate drought stress, phytohormones have attracted substantial attention as a way of reducing stress on plants. Brassinosteroids (BRs) are one of the most important phytohormones that help plants survive against environmental stresses such as drought. In plants, BRs play an important role in growth and development. BRs regulate different plant physiological functions such as leaf photosynthesis, lateral root development, seed germination, root functioning, secondary metabolite production, hormonal regulation, maintaining antioxidant defense system, and balanced redox homeostasis. A wide range of stresses can be tolerated by plants through BRs. A key part of the chapter is to explain how BRs function in plants during drought-induced oxidative damage at physiological, molecular, and cellular levels.