BxALDH as a potential target of fluensulfone for controlling Bursaphelenchus xylophilus in industrial pine trees

Chemical control remains the primary strategy for managing Bursaphelenchus xylophilus , a pathogen which has severely compromised the industrial and ecological value of pine trees and has exhibited outbreak trends across Asia and Europe. To mitigate resistance development caused by overreliance on a limited number of nematicides, we evaluated the nematicidal activity of fluensulfone (FLU) against B. xylophilus and identified its potential target. The 48-h median lethal concentration (LC₅₀) of FLU was 57.73 μg•mL −1 , which was lower than that of abamectin, and FLU markedly inhibited behavioral parameters of B. xylophilus. Integrated transcriptomic and metabolomic analyses identified glycerolipid metabolism as the major FLU-responsive pathway, the gene BxALDH annotated to aldehyde dehydrogenase (ALDH) was selected for validation. RT-qPCR and triglyceride quantification confirmed the pathway perturbation. Co-application of FLU with ds ALDH significantly increased the sensitivity of nematodes and inhibited behavioral parameters. Silencing of BxALDH alone triggered pronounced lipid accumulation, lipotoxicity, and cuticle rupture. Transcriptomic data following ds ALDH treatment revealed disruption of membrane-associated and lipid metabolic pathways. Comprehensive analysis of transcriptomics following FLU and ds ALDH treatments suggested that BX05G2279 and BX01G0496 might participate in the regulation of BxALDH . Molecular docking and molecular dynamics simulations supported that BxALDH served as the potential target of FLU. Collectively, these findings demonstrated that FLU was a promising candidate nematicide for controlling B. xylophilus. BxALDH , which functions to alleviate FLU-induced accumulation of toxic aldehyde and maintain lipid homeostasis thereby attenuating lipotoxic damage, was the potential target of FLU. This study provides new mechanistic insights into FLU action against B. xylophilus and establishes a theoretical foundation for developing integrated management strategies.