Gamma-selinene synthase catalyzes the first step of dihydroagarofuran sesquiterpene alkaloid biosynthesis in Tripterygium
摘要
Tripterygium wilfordii and T. hypoglaucum, which belong to family Celastraceae, are perennial vine shrubs with medicinal uses in treating rheumatoid arthritis, cancer, and male contraception. Among the bioactive ingredients, the macrocyclic dihydroagarofuran sesquiterpene alkaloids (DASAs), also serving as chemotaxonomic markers of Celastraceae, are well-known for cytotoxicity and insecticidal properties. Despite intensive phytochemical investigations over the last half-century, the DASAs biosynthetic pathway remains unsolved. Here, we mined multi-omics data of Tripterygium species and identified 14 sesquiterpene synthase genes. Detailed characterization revealed that a group of enzymes (TwTPS5, TwTPS16, ThTPS5) catalyzed the key step committed to the biosynthesis of DASAs in Tripterygium, as evidenced by CRISPR/Cas9 knockout of TwTPS5 in T. wilfordii. Our biochemical assay showed that these enzymes converted FPP to gamma-selinene. Homologues in other Celastraceae species (EaTPS3, CaTPS5, and CaTPS6) also produced gamma-selinene, suggesting functional conservation in this DASAs-producing lineage. Notably, knocking out TwTPS5 resulted in a reduction of DASAs and enhanced accumulation of pharmaceutically valuable compounds, generating a safer and innovative medicinal plant resource for future applications.