Multi-omics and Co-expression network insights into aroma formation of suitable oolong tea cultivars during withering...

The aroma quality of oolong tea depends on both processing techniques and cultivars; however, the molecular basis underlying cultivar suitability remains unclear. Six cultivars of tea (Camellia sinensis (L.) O. Kuntze), namely 'Huangdan', 'Meizhan', 'Tieguanyin', 'Jiaming No. 1', 'Yingshuang', and 'Fuding Dabaicha', were analyzed using integrated metabolomic and transcriptomic approaches. Dynamic changes in volatile compounds were monitored during processing, and five key metabolites, including indole, α-farnesene, (E)-nerolidol, (E)-3-hexyl acetate, and jasmine lactone, were identified as markers of processing suitability. Comparative co-expression network analysis between the suitable cultivar 'Huangdan' and the unsuitable cultivar 'Jiaming No. 1' revealed distinct expression patterns of genes involved in aroma biosynthesis, including anthranilate phosphoribosyl ester isomerase (trpF), (3S,6E)-nerolidol synthase (NES1), farnesyl diphosphate farnesyltransferase (FDFT1), diphosphomevalonate decarboxylase (MVD), geranyl diphosphate synthase type II (GGPS), acyl-CoA oxidase (ACX), 1,2-oxidophytodienoate reductase (OPR), acetyl-CoA acyltransferase I (ACAA1), and jasmonic acid-O-methyltransferase (JMT). These findings elucidate the molecular mechanisms underlying cultivar suitability in oolong tea and provide a foundation for cultivar selection and processing optimization.