Functional Study on Cytochrome P450 in Response to L(−)-Carvone Stress in Bursaphelenchus xylophilus

Bursaphelenchus xylophilus(PWN) causes pine wilt disease (PWD), which is one of the most devastating pine diseases worldwide. Cytochrome P450 (CYP) catalyzes the biosynthetic metabolism of terpenoids and plays an important role in the modification of secondary metabolites in all living organisms. We investigated the molecular characteristics and biological functions ofBx-cyp29A3inB. xylophilus. The bioinformatics analysis results indicated thatBx-cyp29A3has a transmembrane domain and could dock with L(−)-carvone. The gene expression pattern indicated thatBx-cyp29A3was expressed in 0.2, 0.4, 0.6, 0.8, and 1.0 mg/mL L(−)-carvone solutions. TheBx-cyp29A3expression increased in a dose-dependent manner and peaked at 24 h of exposure when the L(−)-carvone solution concentration was 0.8 mg/mL. However, the gene expression peaked at 0.6 mg/mL after 36 h. Furthermore, RNA interference (RNAi) indicated thatBx-cyp29A3played an essential role in the response to L(−)-carvone. The mortality rates of theBx-cyp29A3knockdown groups were higher than those of the control groups in the 0.4, 0.6, 0.8, and 1.0 mg/mL carvone solutions after 24 h of exposure or 36 h of exposure. In summary, bioinformatics provided the structural characteristics and conserved sequence properties ofBx-cyp29A3and its encoded protein, which provided a target gene for the study of the P450 family ofB. xylophilus. Gene silencing experiments clarified the function ofBx-cyp29A3in the immune defense ofB. xylophilus.This study provides a basis for the screening of new molecular targets for the prevention and management ofB. xylophilus.Keywords:cytochrome P450;L(−)-carvone;Bursaphelenchus xylophilus;RNAi