The volatile 1‐nonanol suppresses Verticillium dahliae through impairing mitochondrial respiration and glutathione metabolism

BACKGROUND: Verticillium wilt, caused by Verticillium dahliae, is a devastating soilborne vascular disease that threatens global agricultural production. Volatile organic compounds (VOCs) from beneficial microorganisms have emerged as promising eco-friendly alternatives to chemical fumigants for disease control. Here, we investigated the antifungal activity and multitarget inhibitory mechanisms of 1-nonanol, a VOC produced by Pseudomonas aurantiaca ST-TJ4, against V. dahliae. RESULTS: 1-Nonanol exhibited potent antifungal activity, completely inhibiting spore germination at 50 μL. Transcriptomic analysis revealed 1045 differentially expressed genes, of which 849 were downregulated, with enriched pathways related to respiration, redox processes, cellular detoxification and cell wall degradation. Physiological assays showed significant decreases in intracellular ATP levels, reduced activities of mitochondrial complex III, succinate dehydrogenase and malate dehydrogenase, and a substantial loss of mitochondrial membrane potential. Molecular docking identified that 1-nonanol targets key residues (ARG287 in DIC; THR233 and LEU323 in BCS1), leading to mitochondrial dysfunction. Additionally, 1-nonanol depleted glutathione metabolism, resulting in excessive reactive oxygen species accumulation. Exogenous GSH partially restored fungal growth, reduced 1-nonanol-induced ROS fluorescence intensity by 55.82%, and restored the JC-1 red/green fluorescence ratio to 59.10% of the CK level. CONCLUSION: 1-Nonanol exerts multi-target inhibition against V. dahliae by disrupting both mitochondrial energy metabolism and redox homeostasis. This supports repurposing 1-nonanol as a bio-based soil fumigant for sustainable Verticillium wilt control.