Full-length transcriptome sequencing provides insights into chlorogenic acid biosynthesis in Lonicera japonica

Lonicera japonica Thunb. is a significant medicinal resource within traditional Chinese medicine, exhibiting a variety of pharmacological properties. Previous studies reported that the major bioactive compound in L. japonica was chlorogenic acid (CGA), while the mechanism of CGA biosynthesis remained unknown due to the limited genome information. In the present study, PacBio single molecule real-time (SMRT) sequencing technology was employed to conduct the inaugural full-length transcriptome sequencing of the honeysuckle cultivar 'Huajin 6'. A total of 97,588 high-quality transcripts, with an average length of 2,883 base pairs, were generated and annotated using the NR, GO, KOG, and KEGG databases. The coding sequences (CDS), transcription factors, simple sequence repeats (SSR), and long non-coding RNA (lncRNA) transcripts were predicted. The key genes encoding hydroxycinnamoyl-CoA quinate transferase (HQT) in CGA biosynthesis were isolated through the combination analysis of transcriptomic data and CGA content in flowers at different development stages. MYB genes that potentially regulated the transcription of HQT were further identified. Taken together, these results provide valuable genetic resources to assist the molecular study of L. japonica genes, which will facilitate the quality improvement of L. japonica cultivars.