Brassinosteroids Biology in Plants Under Salt Stress: Physiological and Molecular Aspects

Salt toxicity poses a significant threat to crop growth and yield. Many physiological and biochemical processes are regulated by brassinosteroids (BRs), which play a crucial role in salt stress adaptation. Restoration of ionic balance is necessary under salt stress. The accumulation of sodium (Na + ) and chloride (Cl − ) in plant tissues, caused by prolonged exposure to elevated soil salinity levels, disturbs the ionic exchange mechanism within the plant cells. To reduce the occurrences of high Na + concentration in these cellular compartments, BRs act on the ion transport system, which includes Na + channel regulation. Furthermore, BRs activate potassium (K + ) transporters, which not only protect against excessive Na + but also function to restrict Cl − . To lessen the oxidative stress brought on by salt stress, BRs spray helps in the activation of antioxidant defense mechanisms. Hence, BRs have potential to increase antioxidant capacity and reduce oxidative stress, protecting cells from salt-induced desiccation. BRs have a unique role in osmotic adjustment, which is an essential ability in plants’ reactions to salt stress. Different biomolecules such as proline, glycinebetaine, and sugars are involved in the stress tolerance mechanism. These solutes are essential for maintaining cellular turgor pressure and stabilizing various molecules in highly osmotic situations. BRs play a crucial role in preventing plants from losing water and assisting them in surviving under elevated salinity conditions. So, these BRs improve plant's ability to maintain ion balance, protect from oxidative stress, and control osmotic processes. It has been concluded that BRs can contribute to the mitigation of salinity stress.