Integrative analyses of metabolome and transcriptome reveal the regulatory network underlying flavor differences in...

Lychee, a subtropical and tropical fruit, is globally celebrated for its distinctive aroma and flavor. Despite its popularity, the key metabolites and regulatory mechanisms underlying the development of lychee pulp flavor profile are not well characterized. In this study, we utilized HS-SPME-GC-MS/MS and GC-MS/MS to analyze the flavor metabolite profiles of 9 lychee varieties. A total of 132 volatile compounds and 187 metabolites were detected, and a comprehensive metabolic profile of lychee pulp flavor was established. By integrating transcriptome data, we elucidated comprehensive regulatory networks for terpene metabolites, which influence lychee aroma, and for sugar and organic acid metabolites, which affect lychee taste. Network analysis enabled the identification and validation of four terpene synthase (TPS) genes involved in terpene synthesis, as well as LcSS1, LcSPS2, and LcPFK1 genes that regulate sugar metabolism. Furthermore, we identified LcCS1 and LcIDH1 genes related to organic acid synthesis, along with potential transcription factors. Our findings provide novel insights into the regulation of lychee flavor metabolism and constitute a valuable resource for improving the quality of this fruit.