Objective  This paper aims to reveal the molecular mechanism of drug sensitivity of Bursaphelenchus xylophilus to provide a theoretical basis for the control of B. xylophilus.

  Method  In this study, the homologous detoxification gene Bx-pgp23 of Caenorhabditis elegans was obtained from the genome of Bursaphelenchus xylophilus, and PCR amplified the protein-coding region of the gene. Subsequently, the physicochemical properties, hydrophobicity, transmembrane distribution, phosphorylation sites, secondary structure, and tertiary structure of the protein Bx-PGP23 were analyzed and predicted by bioinformatics. The effect of Bx-pgp23 silencing on drug sensitivity of B. xylophilus was analyzed by RNAi technology.

  Result  Bioinformatics prediction indicated that the stability coefficient of PGP protein was 38.31 and the hydrophilic coefficient was −0.018. The tertiary structure predicted that PGP protein had multiple amino acids involved in the formation of α-helix and β-sheet with multiple nucleotide-binding domains and transmembrane domain. The gene silencing of Bx-pgp23 gene was performed by RNAi technology, after that, the expression of Bx-pgp23 gene was changed to 42.65% of the original. The results of the bioassay experiment suggested that after 24 h treatment with 1.5 and 2.5 g/L matrine solution, the mortality rate of pine nematode increased by 7.2% and 6.4% in the RNAi group compared with the control group, respectively. After treatment for 48 h with 1.5 and 2.5 g/L matrine solution, the mortality rate of B. xylophilus in the RNAi group increased by 9.0% and 7.2% compared with the control group.

  Conclusion  Protein Bx-PGP23 was a stable hydrophilic protein with transmembrane efflux function. The Bx-pgp23 gene was successfully cloned and the dsRNA of the gene was synthesized. Bx-pgp23 gene silencing affected the sensitivity of B. xylophilus to matrine solution and the mortality rate of B. xylophilus in the RNAi group was significantly higher than the control group under the same mass concentration of matrine solution. The results demonstrate that the Bx-pgp23 gene plays a positive regulatory role in the regulation of drug metabolism in B. xylophilus.