Deciphering the Genetic Logic of Terpene Diversity in Plants

Angiosperms, representing nearly 90% of all plant species, dominate terrestrial ecosystems thanks in part to their sophisticated chemical communication systems. Among the most important of these chemicals are terpenes, built from simple molecular precursors through specialized pathways. Terpenes serve diverse ecological functions: attracting pollinators, deterring herbivores, mediating plant–microbe interactions, and acting as essential growth regulators such as phytohormones. Their remarkable chemical diversity-over 80,000 structures identified to date-has also made them valuable for pharmaceutical, food, and fragrance industries. However, despite intensive studies of terpene products in model plants, the evolutionary dynamics driving terpene synthase genes (TPSs) diversity and specialization remain poorly understood. Due to these challenges, in-depth research on TPS evolution is needed.

On September 25, 2024, researchers from Zhejiang University and Yazhouwan National Laboratory published (DOI: 10.1093/hr/uhae272) their findings in Horticulture Research. The study systematically analyzed 222 experimentally validated TPS genes from 24 flowering plant species, mapping their evolutionary trajectories and functional outputs. By examining how these genes diversified across different clades, the team revealed how plants generate the staggering chemical repertoire of terpenes that underpin floral aromas, fruit flavors, medicinal compounds, and defense responses, offering a framework for future exploration of plant secondary metabolism.

The researchers demonstrated that the TPS-a, TPS-b, and TPS-g subfamilies, unique to angiosperms, experienced significant expansion compared to the more ancient TPS-c and TPS-e/f clades. This genetic proliferation provided raw material for functional divergence, with many TPSs gaining the ability to catalyze multiple reactions. Intriguingly, enzymes often showed bifunctional or even trifunctional activity in vitro, but in vivo expression was tightly shaped by subcellular localization and substrate availability. For example, some tomato TPSs operate in the cytosol to produce sesquiterpenes, while Arabidopsis counterparts (AtTPS8, AtTPS9, AtTPS20, AtTPS26) localize to plastids, synthesizing diterpenes and sesterterpenes. Lineage-specific expansions, such as Brassicaceae-exclusive TPS duplications, revealed how different plant families evolved unique terpene repertoires. The study also mapped organ-specific TPS expression: certain genes enriched in flowers contributed to fragrance, while others in leaves and roots mediated defense or ecological interactions. By linking evolutionary patterns with chemical outputs, the team demonstrated that gene duplication, diversification, and spatial regulation are the main drivers behind the immense terpene diversity observed in flowering plants.

Terpenes are the language plants use to interact with their environment, from warding off pests to attracting pollinators. Our analysis shows that the extraordinary expansion and specialization of terpene synthase genes gave angiosperms the genetic flexibility to innovate chemically. This not only shaped their evolutionary success but also explains why humans have long relied on plant terpenes for medicine, flavor, and fragrance. Understanding these genetic underpinnings opens new doors for synthetic biology and agricultural improvement."

Prof. Xiuyun Wang, co-corresponding author of Zhejiang University

The findings provide a blueprint for harnessing TPS diversity in biotechnology, agriculture, and medicine. By pinpointing how specific TPS families evolved and function across organs, researchers can more effectively engineer plants to produce desired compounds-from disease-resistant crops to high-value metabolites such as pharmaceuticals, essential oils, and natural flavorings. Moreover, exploring TPS evolution in under-studied angiosperms could uncover new bioactive molecules with untapped commercial or therapeutic potential. Ultimately, deciphering the genetic logic of terpene diversity not only deepens our understanding of plant evolution but also enables targeted innovation in sustainable agriculture and green chemistry.