Brassinosteroids: A Comprehensive Review of its Applications in Agriculture and Horticulture

Abstract

Brassinosteroids are a unique class of plant steroid hormones that play pivotal roles in regulating growth, development, and responses to environmental stresses. Since the landmark discovery of brassinolide in Brassica napus pollen, BRs have been recognized as essential modulators of plant physiology, influencing processes such as cell elongation, vascular differentiation, reproductive development, and senescence. Recent advances in molecular biology and genomics have unravelled the complex signaling pathways of BRs, highlighting their crosstalk with other phytohormones including auxins, gibberellins, and abscisic acid. This intricate network underscores the centrality of BRs in orchestrating plant growth and adaptation under diverse conditions. In agriculture and horticulture, BRs have emerged as promising tools for enhancing crop productivity, resilience, and quality. Exogenous application of BRs has been shown to improve seed germination, root and shoot growth, flowering, and fruit set, while also conferring tolerance to abiotic stresses such as drought, salinity, and extreme temperatures. Furthermore, BRs contribute to biotic stress resistance by strengthening plant immune responses against pathogens and pests. Their role in improving nutrient uptake, photosynthetic efficiency, and post-harvest quality makes them highly relevant for sustainable farming practices. This review synthesizes recent progress in BR research, emphasizing both fundamental physiological insights and practical applications. Special attention is given to their potential in horticultural crops, where BRs can enhance yield, nutritional value, and shelf life. Collectively, BRs represent a powerful avenue for advancing sustainable agriculture and horticulture, bridging fundamental science with applied innovation.