Abstract BACKGROUND Black shank disease caused by Phytophthora nicotianae threatens global tobacco production, while the invasive plant Mikania micrantha is a high‐biomass source of antimicrobial secondary metabolites. To promote the resource utilization of invasive plants for green disease management, this study investigated the antifungal activity and underlying mechanisms of mikanolide, a sesquiterpene lactone derived from M. micranth a, against P. nicotianae . RESULTS Mikanolide inhibited mycelial growth in vitro (EC 50 = 6.519–8.954 μg mL −1 ), outperforming azoxystrobin. Pot trials demonstrated strong in vivo efficacy, reducing disease incidence and index to 33.33% and 11.48%, respectively. Mechanistically, mikanolide disrupted cell membrane integrity and induced oxidative stress by suppressing ATP synthesis and antioxidant enzyme activities. Transcriptomics revealed upregulation of acetyl‐CoA carboxylase and ATP‐dependent protease La, with downregulation of malate synthase A. Molecular docking confirmed strong binding affinities to ATP synthase (−7.3 kcal mol −1 ) and succinate dehydrogenase (−8.0 kcal mol −1 ). CONCLUSION Mikanolide suppresses P. nicotianae through disruption of membrane integrity, oxidative stress, and energy metabolism. This study provides a theoretical basis for the resource utilization of M. micrantha and the green management of P. nicotianae . © 2026 Society of Chemical Industry.
Yang et al. (Sun,) studied this question.