## 5 Conclusions  
In conclusion, we employed SMRT sequencing and RNA-seq strategies to efficiently identify key genes associated with the terpenoid biosynthesis in _A. argyi_. We evaluated temporal expression patterns of these metabolically important genes at four harvest time points, leading to the identification of six key genes, including one 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), one (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (HDS), two 1-deoxy-D-xylulose-5-phosphate reductoisomerase (HDR), and two terpene synthase (TPS) genes that were significantly correlated with the levels of monoterpenes or sesquiterpenens in _A. argyi_ samples. Together, these data provide a robust scientific foundation for future studies exploring the molecular determinants of _A. argyi_ sample quality and optimized sample harvesting, which may support genetic engineering efforts focused on the secondary metabolic pathways within relevant medicinal plants.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/molecules27185948/s1](https://www.mdpi.com/article/10.3390/molecules27185948/s1)]([https://www.mdpi.com/article/10.3390/molecules27185948/s1](https://www.mdpi.com/article/10.3390/molecules27185948/s1)). Figure S1: GC-MS chromatogram in extracted ion chromatogram (EIC) mode of 10 compounds in Folium _A. argyi_ extract. Figure S2: PacBio single-molecule long-read sequencing of _A. argyi_; (A) subread length distribution; (B) length distribution of full-length non-chimeric reads; (C) length distribution of CDSs of all isoforms. Figure S3: Volcano plots exhibiting the differential expression of genes associated with different _A. argyi_ samples. Table S1: Identification of volatile constituents in _A. argyi_ leaves collected at four time points by GC-MS. Table S2: Statistics for polymerases. Table S3: Statistics for subread results. Table S4: Statistics for CCS results. Table S5: PacBio single-molecular long-read sequencing of A. argyi. Table S6: Statistics for isoform results. Table S7: The number of transcripts of _A. argyi_. Table S8: Statistics for transcripts after redundant sequence removal. Table S9: Statistics for CDS prediction results. Table S10: Functional annotation and classification of assembled unigenes in _A. argyi_. Table S11: Candidate 77 transcripts involved in upstream of saponin biosynthesis and their average expression level in different harvest months (April, May, June, and July). Table S12: Primers for qRT-PCR.  
**Author Contributions:** [PERSON] and [PERSON] conceptualized the experiments and research plans; [PERSON] collected the sample; [PERSON], [PERSON] and [PERSON] performed the experiments; [PERSON], [PERSON] and [PERSON] carried out the data and statistical analyses; [PERSON] and [PERSON] acquired funding; [PERSON] and [PERSON] revised the manuscript; [PERSON], [PERSON] and [PERSON] wrote the article. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was supported by the National Natural Science Foundation of China (Grant No. 81903782, 31972215 and 81872948), key technology research and demonstration project of safe and efficient production of genuine medicinal materials (No. 2020-620-000-002-04), and Foundation of Wuhan Health and Family Planning Research (No. wx16c11).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.  
**Conflicts of Interest:** The authors declare on conflict of interest.