Brassinosteroid-Mediated Plant Stress Responses

Brassinosteroids (BRs) are a class of polyhydroxylated steroid phytohormones that orchestrate a wide spectrum of plant developmental processes and bolster tolerance to environmental challenges. Under abiotic stresses such as salinity, drought, temperature extremes and heavy metal toxicity, BRs modulate cellular redox balance, ion homeostasis and hormone crosstalk to preserve growth and productivity. Central to this protective role is the activation of transcription factors within the BR signalling cascade, which in turn up-regulate genes encoding antioxidant enzymes, osmolyte biosynthetic enzymes and membrane transporters. By fine-tuning reactive oxygen species (ROS) levels through enhanced scavenging and by influencing the distribution of sodium, potassium and calcium ions, BRs mitigate oxidative damage and osmotic imbalance. Interactions with abscisic acid, ethylene, salicylic acid and jasmonic acid signalling pathways create an integrated network that dynamically adjusts stomatal behaviour, photosynthetic capacity and stress gene expression. Advances in targeted delivery, genetic engineering of BR biosynthesis or signalling components, and elucidation of the molecular interplay with other hormones underscore the potential for brassinosteroid-based strategies to improve crop resilience and global food security.

Research from Nature Portfolio

Seed priming with 28-homobrassinolide in Brassica juncea significantly enhanced tolerance to the combined stresses of salinity and extreme temperatures. Treated seedlings exhibited reduced hydrogen peroxide accumulation and lipid peroxidation, alongside marked increases in superoxide dismutase, catalase and peroxidase activities, indicating a strengthened antioxidant defence. In tomato, combined application of 24-epibrassinolide and calcium restored photosynthetic performance under salt stress by lowering sodium uptake, stabilising membrane integrity and up-regulating enzymes of the ascorbate–glutathione cycle and osmoprotectant pathways. Research on tomato further revealed that brassinosteroid-induced salt tolerance relies on a signalling nexus involving ethylene and ROS. Brassinosteroid treatment activated ethylene biosynthesis enzymes and downstream signalling components; scavenging of either ethylene or ROS compromised antioxidant enzyme induction and stress resilience, demonstrating the critical interplay between these signalling molecules in BR-mediated defence.

Brassinosteroid-Mediated Plant Stress Responses publication trend

The graph below shows the total number of articles in brassinosteroid-mediated plant stress responses across all publications each year (not limited to Nature Index journals).

Technical terms

Brassinosteroids: A family of steroidal phytohormones that regulate plant growth, development and stress responses.

Reactive Oxygen Species (ROS): Highly reactive molecules derived from oxygen that accumulate under stress and can damage cellular components.

Antioxidant Enzymes: Enzymes such as superoxide dismutase, catalase and ascorbate peroxidase that detoxify ROS and protect cells from oxidative damage.

Ascorbate–Glutathione Cycle: A metabolic pathway that maintains cellular redox homeostasis by recycling key antioxidants.

Na+(K+)/H+ Antiporters (NHX): Membrane proteins that exchange sodium or potassium ions for protons to regulate ion balance under salt stress.

References

1. Enhancing the salt stress resistance of seeds and seedlings via a brassinolide sustained release agent system. Chemical and Biological Technologies in Agriculture (2023).
2. The physiological and molecular mechanism of brassinosteroid in response to stress: a review. Biological Research (2018).
3. 28-homobrassinolide regulates antioxidant enzyme activities and gene expression in response to salt- and temperature-induced oxidative stress in Brassica juncea. Scientific Reports (2018).
4. Exogenous application of calcium to 24-epibrassinosteroid pre-treated tomato seedlings mitigates NaCl toxicity by modifying ascorbate–glutathione cycle and secondary metabolites. Scientific Reports (2018).
5. Ethylene and hydrogen peroxide are involved in brassinosteroid-induced salt tolerance in tomato. Scientific Reports (2016).
6. Exogenous Brassinolide Alleviates Salt Stress in Malus hupehensis Rehd. by Regulating the Transcription of NHX-Type Na+(K+)/H+ Antiporters. Frontiers in Plant Science (2020).