Silencing of cyp-33C9 Gene Affects the Reproduction and Pathogenicity of the Pine Wood Nematode, Bursaphelenchus xylophilus

Abstract

Cytochrome P450 genes are very important for plant-parasitic nematodes to reproduce and to metabolize xenobiotic compounds generated by their host plants. The pine wood nematode (PWN), Bursaphelenchus xylophilus, causes very high annual economic losses by killing large numbers of pine trees across Asia and into Europe. In this study, we used RNA interference (RNAi) to analyze the function of the cyp-33C9 gene of PWN. Our results showed that expression of the cyp-33C9 gene was suppressed successfully after soaking nematodes for 24 h in cyp-33C9 double-stranded RNA (dsRNA). The silencing of the cyp-33C9 gene significantly decreased the feeding, reproduction, oviposition and egg hatch of B. xylophilus. Meanwhile, the migration speed of B. xylophilus in Pinus thunbergii was reduced in the early stages when the cyp-33C9 gene was silenced in the nematodes. Moreover, knockdown of the cyp-33C9 gene in B. xylophilus caused a decrease in pathogenicity to pine trees. These results suggest that the cyp-33C9 gene plays an important role in the reproduction and pathogenicity of B. xylophilus. This discovery identified several functions of the cyp-33C9 gene in B. xylophilus and provided useful information for understanding the molecular mechanism behind pine wilt disease caused by PWN.