Tea aroma refers to the comprehensive olfactory characteristics formed by volatile compounds released during tea growth, processing, and infusion, reflecting the integrated regulation of tea genotype, environmental conditions, metabolic pathways, and manufacturing processes. The accumulation and release of aroma compounds are influenced by multiple regulatory mechanisms, including genetic background; environmental cues such as temperature, light, water status, and herbivory; transcription factors (MYB, bHLH, NAC, TCP, and WRKY); hormone and light signaling pathways; and epigenetic modifications. This review systematically summarizes recent advances in research on tea aroma formation from the perspectives of aroma precursors, glycosyltransferase-mediated modulation, transcriptional and epigenetic regulation, cultivar-specific aroma profiles, environmental factors, and post-harvest processing. In future research, integrated multi-omics approaches will serve as effective strategies for deciphering the genetic and epigenetic bases of tea aroma, providing a theoretical foundation for further elucidating aroma formation and advancing precision breeding and quality improvement.

The tea plant (Camellia sinensis) is an economically important leaf crop in which the flowering process consumes substantial nutrients, thereby negatively impacting tea yield and quality. Therefore, deciphering the molecular basis of floral transition is essential for enhancing tea cultivars and optimizing plantation management. The non-flowering tea plant line ‘Ziyang 1’ (ZY1H), which has failed to flower for several consecutive years, and the normal-flowering cultivar ‘Ziyang’ (ZYQT) were used to study the molecular mechanisms underlying the non-flowering phenotype in ZY1H. Phenotypically, ZY1H exhibited shortened internodes, prolonged vegetative growth, and failure to develop floral meristems. Chromosomal analysis confirmed that ZY1H maintains a normal diploid chromosome number (2n=30), excluding triploidy as a causal factor for its non-flowering trait. Transcriptome analysis revealed an impaired vegetative-to-reproductive transition in ZY1H, manifesting as low expression of SPL genes and sustained high expression of flower-repressive AP2-like genes. Additionally, elevated expression of the flowering repressor SVP and reduced expression of the floral integrator FT further disrupted the convergence of floral inductive signals. Notably, brassinosteroid (BR) levels and CsBZR2 expression were elevated in ZY1H. Functional assays showed that CsBZR2 directly binds the CsFLC promoter and suppresses its expression, thereby blocking the flowering process. Collectively, these results demonstrate that disrupted BR signaling and sustained vegetative growth jointly trigger the floral transition defect in ZY1H. This work provides novel insights into the molecular mechanisms of flowering regulation in tea plants and valuable theoretical support for cultivar improvement.

In this study, the metabolites in the flowers and leaves of single- and double-petal jasmine were determined and compared by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with multivariate statistical analysis. The results showed that a total of 935 metabolites were identified from all samples, including amino acids and derivatives, phenolic acids, nucleotides and derivatives, flavonoids, lignans and coumarins, tannins, alkaloids, terpenoids, organic acids, lipids, saccharides and sugar alcohols, vitamins, and other compounds. Totally 348 and 337 significantly changed metabolites (SCMs) from the flowers and leaves were identified between single- and double-petal jasmine, respectively. The major SCMs were phenolic acids, flavonoids, lipids, saccharides and sugar alcohols. The leaves of double-petal jasmine were rich in flavonoids. In addition, the flavone and flavonol biosynthesis pathways were more active, leading to accumulation of more compounds with biological and pharmacological activities such as nicotiflorin, cynaroside, quercetin, quercetin-3-O-glucoside, astragalin, and afzelin. Lipids were the major unique metabolites in the flowers and leaves of single-petal jasmine. The unique metabolites in the flowers and leaves of double-petal jasmine were more diverse and abundant than those in single-petal jasmine. The results of this study are very meaningful for guiding the development of jasmine resources.

In order to study dynamic changes and variations in aroma between single- and double- petal jasmine flowers (Jasminum sambac) during the opening process, headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was used for qualitative and quantitative analysis of jasmine aroma components at different opening periods. The results showed that phenylacetaldehyde, methyl anthranilate, methyl benzoate, α-farnesene, benzyl acetate were the major aroma components of jasmine flower. The contents of aroma components such as β-ethyl phenylacetate, methyl anthranilate, α-stigmasterol and α-farnesene in single-pedal jasmine flowers initially increased and subsequently decreased during the opening process, and so did the contents of aroma components such as benzyl acetate, cis-3-hexenyl benzoate and benzyl benzoate in double-petal jasmine flowers, being higher at the end than in the beginning of the opening period. In addition, benzaldehyde, phenylacetaldehyde, and β-ethyl phenylacetate were the key substances responsible for the fresh and clean aroma of single-pedal jasmine flowers, while hexyl benzoate, cis-3-hexenyl benzoate, and α-farnesene were the key substances contributing to the strong floral aroma of double-petal jasmine flowers. This study provides a basis for the application of single-pedal jasmine flowers in jasmine tea production.