Herbicidal activity and mode‐of‐action of the natural product aureonitol isolated from Chaetomium coarctatum NEAU ‐ Z3

Abstract BACKGROUND Fungal natural products offer significant advantages, including novel modes‐of‐action (MoAs), high environmental compatibility, safety to nontarget organisms and low resistance risk, making them valuable resources for developing eco‐friendly and effective herbicides. This study evaluated the herbicidal activity of aureonitol, a compound derived from Chaetomium coarctatum NEAU‐Z3, and elucidated its molecular mode‐of‐action. These findings provide a promising compound and theoretical foundation for developing novel and highly effective herbicides. RESULTS Aureonitol exhibited significant herbicidal activity, with median inhibitory concentration (IC 50 ) values of 0.170, 0.122, 0.200 and 0.176 mg mL −1 for shoot growth of Portulaca oleracea L., Echinochloa crus‐galli , Amaranthus retroflexus L. and Setaria viridis (L.) Beauv, respectively, and 0.130, 0.138, 0.186 and 0.106 mg mL −1 for root growth. Postemergence, treated with 0.3 mg mL −1 , significantly reduced weed height and fresh weight by >50%, with P. oleracea showing the highest inhibition (71.93%). Meanwhile, aureonitol induced reactive oxygen species (ROS) accumulation and disrupted redox homeostasis in P. oleracea and E. crus‐galli , thereby inhibited weed growth. Crop safety evaluations confirmed good safety for maize, wheat and rice. Transcriptomic analysis further elucidated the molecular MoA, revealing that aureonitol affects several key metabolic pathways in E. crus‐galli , including diterpenoid biosynthesis and plant hormone signalling, phenylpropanoid biosynthesis, cell‐wall metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis and metabolism. CONCLUSION These findings confirm aureonitol's herbicidal activity and modes‐of‐action, highlighting its potential as a compound for developing novel and highly effective herbicides for agricultural weed management and crop protection. © 2026 Society of Chemical Industry.