The negative effects of environmental stresses, such as low
temperature, high
temperature,
salinity,
drought,
heavy metal stress, and
biotic stress significantly decrease crop
productivity.
Plant hormones are currently being used to induce stress tolerance in a variety of
plants.
Brassinosteroids (commonly known as BR) are a group of
phytohormones that regulate a wide range of
biological processes that
lead to tolerance of various stresses in
plants. BR stimulate BRASSINAZOLE RESISTANCE 1 (BZR1)/BRI1-
EMS SUPPRESSOR 1 (BES1),
transcription factors that activate thousands of BR-targeted
genes. BR regulate
antioxidant enzyme activities,
chlorophyll contents, photosynthetic capacity, and
carbohydrate metabolism to increase
plant growth under stress. Mutants with BR defects have shortened root and shoot developments. Exogenous BR application increases the
biosynthesis of endogenous
hormones such as indole-3-
acetic acid,
abscisic acid, jasmonic
acid,
zeatin riboside,
brassinosteroids (BR), and isopentenyl
adenosine, and
gibberellin (GA) and regulates
signal transduction pathways to stimulate stress tolerance. This
review will describe advancements in
knowledge of BR and their
roles in response to different stress conditions in
plants.