Benzaldehyde inhibits glutathione S-transferase activity and triggers reactive oxygen species accumulation in Meloidogyne incognita.

BACKGROUND: Meloidogyne incognita poses a severe hazard to worldwide agricultural productivity, and emergence of multidrug resistance in this root-knot nematode has further exacerbated this challenge. Benzaldehyde, a volatile organic compound, is a promising nematicidal compound; however, its mode of action against M. incognita remains poorly elucidated. The present study aimed to systematically elucidate the nematicidal mechanism of benzaldehyde against M. incognita. RESULTS: In vitro nematicidal assays demonstrated that benzaldehyde showed a potent nematicidal activity against second-stage juveniles (J2s) and markedly inhibited J2s hatching from eggs. Microscopic observations revealed that J2s treated with 100 mg/L benzaldehyde developed vacuolar structures after 72 h, with a greater abundance of vacuoles observed in the 400 mg/L treatment group. Notably, higher concentrations of benzaldehyde significantly suppressed the activity of glutathione S-transferase (GST), causing reactive oxygen species (ROS) overproduction and nematode death. Molecular docking and dynamics simulations confirmed that benzaldehyde could bind steadily to GST, thus weakening its antioxidant performance. Furthermore, pot experiments showed that benzaldehyde effectively reduced gall formation on cucumber roots caused by M. incognita. CONCLUSION: This study uncovers a novel GST-targeted inhibitory mechanism of benzaldehyde, which shows promising prospects for the exploitation of eco-friendly nematicides. Meanwhile, it proposes an effective measure to curb the progressive multidrug resistance of M. incognita and alleviate severe agricultural economic losses. © 2026 Society of Chemical Industry.