Protective Role of Brassinosteroids in Plants During Abiotic Stress

Abstract

Brassinosteroids (BRs) are a class of steroidal phytohormones that are ubiquitously distributed in the plant kingdom. BRs have always played a significant role in regulating broad aspects of plant growth and development, including germination, the vegetative stage, reproductive development, senescence, and responses to various abiotic stresses. BRs play prominent roles in various physiological processes such as cell division, elongation and expansion, vascular differentiation, pollen tube growth, proton pump activation, membrane polarization, source/sink relationships, ion uptake, regulation of gene expression, nucleic acid and protein synthesis, enzymes activation, and photosynthesis. Moreover, BRs have shown the ability to crosstalk with other phytohormones such as auxin, cytokinin, gibberellic acid, abscisic acid, ethylene, and jasmonic acid in regulating physiological and biochemical processes in plants under abiotic stress. Thus, BRs have been shown to improve plant adaptations to abiotic stresses. This chapter highlights the physiological roles of brassinosteroids in plants and their protective effect under stressed conditions.