Multi-omics analysis of the low temperatures in enhancing the aroma of Oolong tea (Camellia sinensis cv. Yashixiang Dancong)

As tea ( Camellia sinensis L.) consumption continues to grow, its chemical and volatile compounds are becoming increasingly important in defining its quality. The current study analyzed the aromatic compounds in “Yashixiang” tea plants under different temperatures (8 °C, 12 °C, 16 °C, 20 °C, and 24 °C) and different intervals of time (0h, 0.5h, 1h, 3h, 6h, 9h, and 12h) at 16 °C. Gas chromatography-mass spectrometry (GC-MS) was used to detect the volatile components, and transcriptome sequencing was performed to study the aroma substances and terpenoid pathway. The results revealed that at 16 °C, fresh tea leaves aroma substances linalool, methyl salicylate, geraniol, phthalate esters, A-didehydrocorusene, linalool oxide-I, and linalool oxide-II, with floral and woody aroma were predominating with long time period (12h). The two major pathways of terpene biosynthesis (Methylerythritol phosphate (MEP) and Mevalonic acid (MVA) pathway), CsTPS7, CsMK, CsFPS, CsHMGS, CsMVD, CsAACT, CsISPE, and the CsTPSs genes located at the end of terpene synthesis pathway were highly expressed, these compounds significantly contributing to intense and long-lasting aroma at 16 °C. The transcription factors MYB, bHLAH, and WRKY were significantly correlated with the key genes in terpenoid biosynthesis. This study provides important information about how low temperatures enhance tea aroma by affecting terpenoid content and gene expression. • Tea grown at 16 °C had a more potent and lasting aroma, with compounds like linalool and geraniol predominating after 12 h. • Low temperatures led to increased expression of genes in the MVA and MEP pathways, enhancing aroma-related terpenoids. • Cold temperatures boosted gene expression in metabolic and secondary metabolite pathways, contributing to the stronger aroma. • MYB, bHLH, and WRKY transcription factors were linked to the upregulation of terpenoid biosynthesis genes, influencing aroma production.