Molecular Characterization and Functional Analysis of GPCR Gene Bx-srh-1 in Pinewood Nematode (Bursaphelenchus xylophilus)

Bursaphelenchus xylophilus, also known as the pine wood nematode (PWD), which causes pine wilt disease (PWD), is one of the most devastating diseases affecting pine forests globally. G protein-coupled receptors (GPCRs) are crucial in many biological processes and serve as privileged points of communication between cells and the surrounding environment. α-pinene has been found to play a crucial role in combating the infection, colonization, and early stages of pathogenesis caused by B. xylophilus. In this study, we investigated the molecular characteristics and biological functions of the GPCR gene Bx-srh-1 in B. xylophilus. Fluorescence in situ hybridization (FISH) was performed to determine the spatial expression patterns of Bx-srh-1 in B. xylophilus. The results indicated that Bx-srh-1 is expressed in the intestine and subcutaneous tissues of J2 and J3 juveniles and in the spicules of adult males and vulvae of adult females. RNA interference (RNAi) was used to analyze Bx-srh-1 gene function, and we examined the expression patterns of Bx-srh-1 in B. xylophilus under α-pinene stress. The RNA interference indicated that Bx-srh-1 was involved in the reproductive ability and pathogenicity of B. xylophilus; the expression levels of Bx-srh-1 significantly increased after the exposure to α-pinene for 12 h, and they peaked at 48 h. Silencing Bx-srh-1 may therefore lead to a reduction in B. xylophilus reproduction and pathogenicity. These results demonstrate that Bx-srh-1 is related to the feeding behavior, reproduction, pathogenicity, and resistance to α-pinene process of B. xylophilus.