ABSTRACT
Brassinostreoids (BRs) possess a large array of growth and development-regulated functions in plants ranging from morphology to cellular metabolic activity regulation and, at molecular level, change in gene expression as well as modulating the metabolism of nucleic acids and proteins. Because of the number of regulating potentials that BRs have shown in the life cycle of plants, they are considered a sixth class of plant growth regulators (PGRs). Of the number of steroid hormones that help plant synthesis, BRs, whose plant hormonal activity was discovered in 1979, were the first steroid hormones to be detected. BRs are present in almost all plant members ranging from fungi, bryophytes, pteridophytes and gymnosperms to highly evolved organisms in the plant kingdom named angiosperms. Within plants, these steroid compounds are available in almost every part of the plant body, with the highest amount in young tissues and reproductive organs. The ubiquitous presence of these steroid hormones and their metabolism has identified these hormones as having played roles in the long combined evolution of plants and animals. The various regulatory functions that BRs perform in a variety of ways in different plants has attracted the attention of researchers in the field of analytic and synthetic chemistry, biochemistry, plant physiology, stress physiology and agriculture to explore this group of hormones in more depth.
