## 5 Conclusions  
Our research across 115 angiosperms reveals the genomic diversity and evolutionary trajectories of the terpene synthase (TPS) gene family, identifying 3802 TPS genes and categorizing them into five distinct subgroups. This extensive classification highlights significant variability in gene numbers, with adaptive expansion observed in the TPS-a subgroup. Synteny analysis further delineated homologous relationships and evolutionary conservation, identifying 22,035 edges and 1618 nodes that map the genetic architecture and evolutionary pressures shaping these genes. Notably, lineage-specific expansions linked to whole-genome duplications suggest significant evolutionary roles. Our focused study on _R. chinensis_ uncovered a large TPS gene family with a substantial expansion in the TPS-a subgroup. This study enhances our understanding of plant secondary metabolism and sets a foundation for future explorations into the ecological and adaptive significance of TPS genes. It should be acknowledged that our study has certain limitations: the angiosperm-centric sampling may underrepresent early plant lineages, functional validation was limited to RcTPS23, and ecological correlations remain unexplored. These findings hold biotechnological promise for fragrance compound biosynthesis (e.g., engineering TPS-a genes like RcTPS23 for industrial terpene production) and agricultural innovation (e.g., developing pest-resistant crops through volatile organic compound engineering). Future investigations should prioritize integrating multi-omics approaches to link genomic patterns with terpene metabolite profiles, and employing high-throughput CRISPR screening to decipher genotype-phenotype relationships across plant taxa.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/ijms26052113/s1](https://www.mdpi.com/article/10.3390/ijms26052113/s1)]([https://www.mdpi.com/article/10.3390/ijms26052113/s1](https://www.mdpi.com/article/10.3390/ijms26052113/s1)).  
Conceptualization, Y.H.; Methodology, Q.L., Y.P., T.Z. and X.L.; Software, Q.L., T.Z. and X.L.; Formal analysis, Y.P. and Q.D.; Investigation, Q.Y.; Resources, Q.D. and Q.Y.; Data curation, Y.P., T.Z., X.L. and Y.H.; Writing--original draft, Q.L. and Y.P.; Writing--review & editing, T.Z. and Y.H.; Visualization, Q.L., Q.D. and Q.Y.; Supervision, Q.Y.; Funding acquisition, Y.H. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Key Research and Development Project of China (2023 YFD1200105), China; National Natural Science Foundation of China (32471938, 31800594), China; Fundamental Research Funds for the Central Universities (QNTD202306), China; and Beijing Natural Science Foundation (6174045), China.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data are contained within the article and Supplementary Materials.  
**Acknowledgments:** Thanks to [PERSON] of Northeast Normal University for his guidance on enzyme activity experimental techniques.  
**Conflicts of Interest:** The authors declare no conflict of interest.