Angiosperms are prolific producers of structurally diverse terpenes, which are essential for plant defense responses, as well as the formation of floral scents, fruit flavors, and medicinal constituents. Terpene synthase genes (TPSs) play crucial roles in the biosynthesis of terpenes. This study specifically focuses on the catalytic products of 222 functionally characterized TPSs in 24 angiosperms, which mainly comprise monoterpenes, sesquiterpenes, diterpenes, and sesterterpene. Our systematic analysis of these TPSs uncovered a significant expansion of the angiosperm-specific TPS-a, b, and g subfamilies in comparison to the TPS-e/f and c subfamilies. The expanded subfamilies can be further partitioned into distinct branches, within which considerable functional innovation and diversification have been observed. Numerous TPSs exhibit bifunctional or even trifunctional activities in vitro, yet they exhibit only a single activity in vivo, which may be largely determined by their inherent properties, subcellular localization, and the availabilities of endogenous substrates. Additionally, we explored the biological functions of terpenes in various organs and tissues of angiosperms. We propose that the expansion and functional divergence of TPSs contribute to the adaptability and diversity of angiosperms, facilitating the production of a broad spectrum of terpenes that enable diverse interactions with the environment and other organisms. Our findings provide a foundation for comprehending the correlation between the evolutionary features of TPSs and the diversity of terpenes in angiosperms, which is significant for terpene biosynthesis research.

中文翻译：

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被子植物中萜烯合酶基因的扩展和功能分化：萜烯多样性的驱动力


被子植物是结构多样的萜烯的多产生产者，这些萜烯对于植物防御反应以及花香、水果风味和药用成分的形成至关重要。萜烯合酶基因（TPS）在萜烯的生物合成中发挥着至关重要的作用。本研究特别关注24种被子植物中222种功能表征的TPS的催化产物，主要包括单萜、倍半萜、二萜和二倍萜。我们对这些 TPS 的系统分析发现，与 TPS-e/f 和 c 亚家族相比，被子植物特异性 TPS-a、b 和 g 亚家族显着扩展。扩展的亚家族可以进一步分为不同的分支，其中观察到相当多的功能创新和多样化。许多TPS在体外表现出双功能甚至三功能活性，但它们在体内仅表现出单一活性，这可能很大程度上取决于它们的固有特性、亚细胞定位和内源底物的可用性。此外，我们还探讨了萜烯在被子植物各种器官和组织中的生物学功能。我们认为，TPS 的扩展和功能分化有助于被子植物的适应性和多样性，促进广谱萜烯的产生，从而实现与环境和其他生物体的多种相互作用。我们的研究结果为理解被子植物中TPS的进化特征与萜烯多样性之间的相关性提供了基础，这对于萜烯生物合成研究具有重要意义。