Integrated analysis of potassium acetate effects on barley: growth, physiological traits, genetic diversity, and DREB gene regulation

Potassium acetate is a soluble source of potassium that can improve plant growth and stress tolerance. Although potassium is a recognized necessary macronutrient, the precise physiological and molecular mechanisms associated with its acetate form in plants are inadequately understood. However, limited information exists on the impact of potassium acetate on critical stress-responsive genomic pathways, particularly those governed by Dehydration-Responsive Element-Binding (DREB) transcription factors, which are essential for abiotic stress tolerance. The significant information gap regarding potassium acetate-induced stress responses was resolved via integrated physiological and molecular investigations: Optimal potassium acetate concentrations were found to enhance barley growth and stimulate DREB gene expression in a dose-dependent manner. This study assessed the effects of potassium acetate (0–4 mM) on the germination, growth-related morphological and physiological traits, molecular diversity, and expression of stress-responsive genes in barley (Hordeum vulgare L., cv. Giza 134). Germination and vegetative growth significantly improved at 1–2 mM K-acetate, whereas higher concentrations (≥ 3 mM) induced growth inhibition. Physiological analysis revealed elevated levels of chlorophyll b, carotenoids, xanthophylls, and protein content at moderate concentrations, whereas reductions were observed at 3 mM, indicating a concentration-dependent stress threshold. Random amplified polymorphic DNA (RAPD) and Inter-simple sequence repeat (ISSR) analyses revealed significant genetic polymorphism among treatments, with ISSR markers demonstrating greater variability (25.6%) than RAPD markers (17.7%). Sequencing confirmed the presence of a conserved DREB gene, and its expression was significantly increased compared with the control, after treatment with 2–3 mM K-acetate. Potassium acetate at optimal concentrations (1–2 mM) acts as a strong bio-stimulant for barley by increasing protein content, photosynthetic pigments, and vegetative development. Additionally, by upregulating DREB gene expression and causing genetic diversity, this therapy initiates important stress-tolerance processes, offering a promising method for enhancing crop resilience under abiotic stress.