Exogenous 24-Epibrassinolide alleviates salt stress in Okra (Abelmoschus esculentus L.) by increasing the expression of SOS pathway genes (SOS1-3) and NHX1,4.

Abstract

Given the rising population and food demand, it is imperative to devise solutions to enhance plant resilience against abiotic stresses. Salinity stress impacts plant growth but also hampers plant performance and productivity. Plant hormones have emerged as a viable remedy to mitigate the detrimental effects of salinity stress on plants. This study delved into the molecular investigation of the impact of 24-Epibrassinolide (EBL) on Okra plants (Abelmoschus esculentus L.) under two levels of salinity stress (75 and 150 mM), scrutinizing morphological, biochemical, and physiological parameters. Salinity stress led to a decline in growth, pigment and protein content, with EBL application ameliorating these indicators, albeit insignificantly impacting protein levels. Salinity triggered an upsurge in soluble sugars, proline, antioxidant enzymes (CAT, SOD, GP, and APX), and sodium levels, while reducing potassium and micronutrient concentrations (copper, iron, zinc). It downregulated the expression of NHX1, NHX4, SOS1, SOS2, and SOS3 genes. EBL treatment bolstered potassium and micronutrient uptake, upregulated gene expression and enzymatic antioxidants, and elevated soluble sugar and proline levels. Analysis of the outcomes across these parameters suggests that EBL holds promise as an effective agent in mitigating salinity stress in Okra plants.