Abstract:
Plants absorb and utilize various essential and beneficial elements to complete the whole life cycles. Inefficient nutritional elements or excessive toxic heavy metals in soil will inhibit plant growth, development, and the formation of yield and crop quality. The heavy metals existed in crops may even damage human health through food chain migration. Phytohormone brassinosteroid, as a growth-promoting hormone, involves in various procession of plant growth and development, and plays an important role in coping with biotic and abiotic stresses. The paper reviews the main processes and key genes involved in the synthesis, transport, metabolism and signal transduction of brassinosteroid in plants, and the molecular mechanism of brassinosteroid involved in the regulation of nutrient stress such as nitrogen, phosphorus, boron, and iron, and the physiological and molecular mechanisms of brassinosteroid involved in alleviating the stress of toxic heavy metals such as cadmium, arsenic, lead and chromium. BES1/BZR1, the key transcription factors in brassinosteroid signaling, will change their expression patterns when plants are subjected to nutrient stress, and then affect the expression of downstream target genes to adapt to the nutrient stress. Under heavy metal stress, exogenous spraying of brassinosteroid can reduce the accumulation of heavy metals in plants, reduce the adverse effects on plant growth, improve the photosynthetic capacity, increase the activity of antioxidant enzymes to cope with the outbreak of reactive oxygen species, and then enhance the tolerance to heavy metal stresses. Exogenous application of brassinosteroid in agricultural production is also found beneficial to plant growth and development, and high resistance to adverse conditions, therefore, showing broad prospects in agricultural production in improving crop stress resistance and achieving high and stable yield.