Metabolomic and transcriptomic analyses reveal the formation mechanism of bitter components in blue honeysuckle

Blue honeysuckle fruits exhibit a diverse flavor profile and are nutritionally rich, with bitter compounds having recently garnered increasing attention. This study integrates sensory analysis and metabolomics to identify key bitter metabolites responsible for the variation in bitterness observed among blue honeysuckle cultivars. The results indicate that loganic acid, arbutin, and coumarins are primary contributors to bitterness variation. Through differential gene expression (DEG) analysis of transcriptomic data, a biosynthetic pathway for bitter compounds, primarily involving polyphenol and monoterpene synthesis, was elucidated. A total of 15 potential bitter compounds were found to be regulated by 17 distinct gene families. Furthermore, weighted gene co-expression network analysis (WGCNA) identified gene modules linked to bitterness and selected 15 key regulatory factors, including 7 MYB, 4 bZIP, and 4 bHLH genes, potentially involved in the biosynthesis of bitter compounds. These genes are likely to play crucial roles in the biosynthesis of bitter compounds. The findings provide a critical theoretical foundation for understanding the mechanisms underlying blue honeysuckle bitterness and its molecular regulation. • Blue honeysuckle bitterness varies significantly across cultivars and maturity stages. • Twenty bitter compounds (polyphenols/terpenoids) are identified as key contributors. • Multiomics unraveled the bitter compounds biosynthetic pathways in blue honeysuckle. • WGCNA revealed the regulatory networks controlling bitter compound biosynthesis.