Expression of the Thaumatin-Like Protein-1 Gene (--) from Pine Wood Nematode Affects Terpene Metabolism in Pine Trees.

Pine wilt disease is a major forest disease worldwide, including in China, where it has severely damaged pine forest ecosystems, and the pathogen is pine wood nematode (). The thaumatin-like protein-1 gene (--) is a key gene associated with . pathogenicity, which is also responsive to α-pinene. In this study, an examination of seedlings infected by . revealed that monoterpene (sesquiterpene) levels peaked on days 15 and 27 (days 18 and 27). Meanwhile, . - expression levels were high on days 3, 12, and 27, which were consistent with the expression of key enzymes genes in the terpene biosynthesis pathway. The functional similarity of . Bx-TLP-1 and . Pm-TLP suggests Bx-TLP-1 and Pm-TLP may have similar roles in . . There was also no secondary accumulation of terpenes in . seedlings during . treated with dsRNA targeting -- (dsTLP1) infections, reflecting the decreased pathogenicity of . and the delayed disease progression in pine trees. And the results of micro-CT showed that the degree of cavitation for the trees inoculated with Bx-TLP-1 (0.3811 mm) was greater than that for the trees inoculated with dsTLP1 PWNs (0.1204 mm) on day 15 after inoculation. Results from this study indicated that . -- gene may induce the upregulated expression of related genes encoding enzymes in the terpene synthesis pathway of . , resulting in the accumulation of terpenes, which also provided an insight to investigate the . pathogenicity in the future.