Cultivation altitude is a comprehensive environmental factor that significantly affects tea quality. To gain a deeper understanding of the effect of cultivation altitude on tea metabolites, a widely targeted metabolomic method based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) was used to analyze tea samples derived from three altitudes (86 m, 256 m, and 880 m) of two cultivars, ‘Mingke 1’ (MK) and ‘Fuyun 6’ (FY). The results showed that distinct groups of tea samples from different altitudes and cultivars were observed based on PCA. A total of 64 and 56 altitude-related differential metabolites were identified in MK and FY, respectively. Among them, 16 compounds were consistent in both cultivars and were clustered in the metabolic pathways for flavonoid (11 compounds), amino acid (3), and fatty acid (2). The content of all flavonoids and one amino acid (L-aspartic acid) gradually decreased with increasing altitude; on the contrary, the others showed an opposite trend. Furthermore, we identified 57 differential metabolites between two cultivars. Two specific compounds (8-C-hexosyl chrysoeriol O-hexoside and pelargonidin 3-O-β-D-glucoside) were exclusively found in MK, while one compound (4-hydroxybenzoic acid) was present only in FY. These findings offer insight into the metabolic responses of tea plants to different altitudes, providing further understanding on the influence of the environment on tea plants.

Aroma is an important factor in the measurement of the quality and market value of oolong tea. However, it is hard to develop an oolong tea with good aroma quality using unsuitable tea varieties. To explore the key factors of tea varieties in the formation of oolong tea aromas, the fresh leaves of the Chungui variety (CG, suitable for oolong tea, Camellia sinensis (L.) O. Kuntze) and the Fuyun No. 6 variety (F6, unsuitable for oolong tea, Camellia sinensis (L.) O. Kuntze) were harvested and treated by withering and mechanical stress in order. Then, aroma, transcriptome, and jasmonate (JA) contents, and weighted gene co-expression network analysis (WGCNA), of samples were investigated. The contents of characteristic oolong tea aromas, including indole, (E)-β-ocimene, (E)-nerolidol, α-farnesene, and jasmine lactone, were all accumulated in much higher quantities in the CG variety after withering and mechanical stress. Accordingly, the coding genes of aroma formation synthases TSB2, OCS, NES, AFS, and LOX1, and related genes in MVA, MEP, and ALA pathways, were all much more highly activated. These differential reactions are mainly caused by the higher accumulation of jasmonates, especially methyl jasmonate, a type of important plant signal chemical, in CG after mechanical stress. WGCNA analysis indicated 34 different transcription factors from different families are predicted to be involved in this jasmonate-responsive reaction.