Dynamic evolution and formation mechanisms of aroma compounds in Qianmei 502 black tea during processing: insights from transcriptomic and metabolomic analyses

To investigate the aroma evolution and underlying molecular mechanisms during the processing of Qianmei 502 black tea, we conducted an integrated analysis using transcriptomic and broadly-targeted volatile metabolomic approaches. Our study identified 856 volatile metabolites and 18,633 genes through metabolomic and transcriptomic profiling. Integrated analysis revealed that α -linolenic acid metabolism, phenylalanine metabolism, glycerolipid metabolism, and monoterpenoid biosynthesis constituted the key metabolic pathways during tea processing. Notably, the elevated expression of ADH1 and TAT gene families, coupled with dynamic changes in phenylethanal, phenylethanol, geraniol, ( Z )-3-hexenol, and indole concentrations, were identified as critical factors contributing to the distinctive sweet floral aroma characteristics of Qianmei 502 black tea. • In total, 18,633 genes and 856 volatile substances were found by transcriptome and metabolome. • Key pathways: α-linolenic acid, phenylalanine, and glycerolipid metabolism, plus monoterpenoid biosynthesis. • ADH1/TAT upregulation and phenylethanal, phenylethanol, geraniol, (Z)-3-hexenol, indole dynamics drive Qianmei 502 black tea's sweet floral aroma.