# Integrated Transcriptomic and Metabolomic Analyses Reveal Key Genes Involved in Phenylpropanoid Metabolism in Lonicera macranthoides Flowers

## TL;DR

This study combines gene and metabolite data to identify key genes involved in the production of medicinal compounds in Lonicera macranthoides flowers.

## Contribution

The study reveals a stage-specific regulatory network for phenylpropanoid metabolism in Lonicera macranthoides flowers.

## Key findings

- The phenylpropanoid biosynthesis pathway is a key hub during flower development in Lonicera macranthoides.
- Stage-specific metabolite accumulation patterns were identified, with distinct peaks for caffeoylquinic acid and other acids.
- A regulatory module containing 71 transcription factors was found to correlate with key phenolic acids.

## Abstract

Background: Lonicera macranthoides (L. macranthoides) is a traditional Chinese medicinal plant, the flower buds of which are rich in bioactive compounds, such as chlorogenic acids (CGAs) and flavonoids, and exhibit diverse pharmacological activities. Methods: Integrated transcriptomic and metabolomic analyses were conducted across three floral developmental stages: flower bud (FB), white flower (WF), and golden flower (GF). Results: Clustering analysis revealed distinct molecular profiles, with the WF and GF stages clustering together and clearly separating from the FB stage. The most significant metabolomic variation was observed between the GF and FB stages. KEGG enrichment analysis consistently highlighted the phenylpropanoid biosynthesis pathway as a key hub. Stage-specific accumulation patterns were identified for critical metabolites: caffeoylquinic acid peaked at the WF stage, while ferulic acid, sinapic acid, cinnamic acid, and p-coumaric acid reached their highest levels at the GF stage. Within this pathway, we identified 11 DEGs encoding the core enzymes, alongside 15 associated DAMs. The expression trends of four PAL genes were fully consistent with the accumulation of related precursors, and F5H expression correlated with its downstream product, sinapic acid. WGCNA identified a key module highly correlated with key phenolic acids, containing 71 transcription factors, including MYB, bHLH, WRKY, and AP2/ERF families, potentially forming a complex regulatory network for phenylpropanoid biosynthesis. Conclusions: This study deciphers the stage-specific regulatory network of CGA biosynthesis, providing critical insights and genetic resources for cultivating high-medicinal-content varieties of L. macranthoides.