Functional characterization and evolutionary diversification of sesquiterpene synthases in Cunninghamia konishii

Cunninghamia konishii is a precious coniferous species endemic to Taiwan and is highly valued for its superior timber quality and durability, which make it an important resource for construction and furniture manufacturing. Furthermore, its characteristic fragrance represents a valuable natural product with potential applications in essential oils, perfumes, and related aromatic industries. The characteristic aroma of C. konishii is mainly derived from volatile terpenes; however, the biosynthesis of these compounds remains poorly understood. In this study, six full-length sesquiterpene synthase genes were isolated and functionally characterized to elucidate the molecular basis of terpene biosynthesis in C. konishii. Functional analyses revealed that CkTPS1 and CkTPS2 primarily produced dauca-4(11),8-diene, CkTPS3 produced germacrene A, CkTPS4 produced β-caryophyllene, CkTPS5 produced cubebol, and CkTPS6 produced δ-cadinene. These findings provide new insights into volatile terpene biosynthesis in C. konishii and advance our understanding of the functional diversification and evolutionary trajectories of sesquiterpene synthases in conifers.