Calmodulin-binding transcription activators (CAMTAs) are evolutionarily conserved transcription factors and have multi-functions in plant development and stress response. However, identification and functional analysis of tea plant (Camellia sinensis) CAMTA genes (CsCAMTAs) are still lacking. Here, five CsCAMTAs were identified from tea plant genomic database. Their gene structures were similar except CsCAMTA2, and protein domains were conserved. Phylogenetic relationship classified the CsCAMTAs into three groups, CsCAMTA2 was in group I, and CsCAMTA1, 3 and CsCAMTA4, 5 were, respectively, in groups II and III. Analysis showed that stress and phytohormone response-related cis-elements were distributed in the promoters of CsCAMTA genes. Expression analysis showed that CsCAMTAs were differentially expressed in different organs and under various stress treatments of tea plants. Three-hundred and four hundred-one positive co-expressed genes of CsCAMTAs were identified under cold and drought, respectively. CsCAMTAs and their co-expressed genes constituted five independent co-expression networks. KEGG enrichment analysis of CsCAMTAs and the co-expressed genes revealed that hormone regulation, transcriptional regulation, and protein processing-related pathways were enriched under cold treatment, while pathways like hormone metabolism, lipid metabolism, and carbon metabolism were enriched under drought treatment. Protein interaction network analysis suggested that CsCAMTAs could bind (G/A/C)CGCG(C/G/T) or (A/C)CGTGT cis element in the target gene promoters, and transcriptional regulation might be the main way of CsCAMTA-mediated functional regulation. The study establishes a foundation for further function studies of CsCAMTA genes in stress response.

Tea flower, with characteristic flavor formed during blooming, are a significant tea resource. However, studies on the volatile compounds of tea flower and their aroma characteristics during flowering are scarce. In this study, the odor characteristics of tea flower during blooming were comprehensively investigated by GC–MS, PCA, ACI determination and sensory evaluation. The tea flower of unopened buds (TF-S1) contained the highest alcohol amounts, while fully opened tea flowers (TF-S3) had the highest heterocyclic compounds. Half-opened tea flowers (TF-S2) had the most volatile compounds, including high levels of linalool and its oxides, and low levels of (Z)-3-hexen-1-ol. Acetoin and cosmene were first identified in TF-S1 and TF-S2, respectively. The major ACI components differed, with linalool being prominent exhibiting ACI above 27 in all samples. Acetophenone, unique to TF-S2 with ACI of 57.35, contributed to sweet odor. Furthermore, PCA analysis and sensory evaluation revealed distinct aroma characteristics among the samples. Overall, TF-S2 and TF-S3 had higher volatile amounts and better aroma properties with floral, powdery or almond-like odors. These results advance the understanding of aroma properties of tea flower during blooming, and provide a reference for resource utilization and promotion of the application in food or cosmetics industries.

C-repeat binding factors/dehydration responsive element binding factors 1 (CBFs/DREB1s) are a small family of transcription factors that play important roles in plant resistance to various external stresses. However, functional characterization of tea plant (Camellia sinensis L.) CBF gene (CsCBF) was still seldom reported. Here, functional study of the cold-responsive CBF gene (CsCBF2) was done. Results showed that CsCBF2 had conserved AP2 DNA-binding domain and the typical PKK/RPAGRxKFxETRHP and DSAWR signature sequences of CBF/DREB1. Yeast one-hybrid and transcription activation assays revealed that the activation domain of CsCBF2 could activate the reporter gene expression, and the N terminal of CsCBF2 displayed an inhibitory effect. Although CsCBF2 was conserved to bind the C-repeat/dehydration-responsive element (CRT/DRE), intact CsCBF2 protein preferred the CRT cis element. Under normal growth conditions, CsCBF2-overexpressing tobacco plants (CsCBF2-OX) exhibited lighter green leaf color, growth retardation, and dwarfism. Smaller leaf of CsCBF2-OX was only seen in eight weeks after been sown in soil. Under cold, salinity, or drought stress, CsCBF2-OX displayed better growing with longer roots, heavier fresh weight, higher germination rate, and accumulated more proline and sugar contents, but lower electrolyte leakage. The results demonstrated that CsCBF2 enhanced plant tolerance to multiple abiotic stresses.

Chronic metabolic diseases (CMDs), characterized by Type 2 diabetes mellitus (T2DM), obesity, and atherosclerosis, represent a global health crisis, significantly impairing patients' quality of life and imposing substantial socioeconomic burdens. Although current pharmacological interventions can mitigate disease progression, long-term administration carries the inherent risks of adverse effects. Medicinal food homologous (MFH) substances are emerging as promising interventions for metabolic disorders owing to their multitarget bioactivity, favorable safety profiles, and high patient compliance. Recent research demonstrates that tea catechins and their oxidative polymers exert beneficial effects against metabolic dysregulation through diverse mechanisms, including modulation of glucolipid metabolism, amelioration of insulin resistance, and anti-inflammatory actions. This review systematically synthesizes the molecular mechanisms and key signaling pathways underpinning the beneficial effects of tea catechins and their oxidative polymers in obesity, diabetes, and related syndromes, which include regulating glucolipid metabolism, improving insulin resistance, and exerting anti-inflammatory and antioxidant activities. Furthermore, the article critically discusses the clinical translational potential of these compounds, highlighting future applications as dietary supplements or adjuvant therapeutics. Collectively, these findings establish a theoretical foundation for developing novel natural product-based therapeutics against metabolic disorders.

Green tea quality is largely determined by the metabolite profile of fresh leaves. However, the time-of-day-dependent dynamics of these metabolites remain largely unknown in Xinyang Maojian (XYMJ), a premium Chinese green tea. In this study, we performed the first integrative transcriptomic and metabolomic analysis of Camellia sinensis cv. Xinyang 10 shoots (one bud and one leaf) sampled at 7:00, 13:00, and 18:00 under field conditions with light intensities of 19.2, 113, and 5.4 klx, respectively. We identified 525 differentially accumulated metabolites and 19,767 differentially expressed genes exhibiting distinct time-of-day-dependent patterns. Physiological measurements confirmed significant fluctuations in starch, soluble sugars, chlorophyll, relative water content, and polyphenols throughout the daytime. A key finding was a daytime carbon allocation trade-off: primary metabolism (starch biosynthesis, glycolysis, TCA cycle) peaked at 13:00, whereas secondary metabolism (flavonoids, theaflavins, phenolic acids, anthocyanins) dominated at 18:00, supported by strong negative correlations between primary and secondary metabolic modules. Chlorophyll and oligomeric catechins peaked at 7:00; theaflavins at 13:00; and starch, soluble sugars, theanine, and organic acids at 18:00. Light-responsive transcription factors (bZIP, NF-Y, HD-Zip, SPL, ARF, MADS) and other regulators (MYB, AP2/ERF, WRKY, NAC, GRAS, bHLH) exhibited time-specific expression, sequentially modulating flavonoid, caffeine, and theanine biosynthesis, along with specific gene modules including SS3/SS4 (starch synthesis), BAM3 (starch degradation), FBA1 (carbon fixation), CYP72A219 (terpenoid metabolism), and L7A (theaflavin biosynthesis). Evening-harvested leaves accumulated higher levels of theanine (umami) and soluble sugars (sweetness), whereas morning leaves were enriched in astringent catechins and flavonols. This multi-omics dissection of time-of-day-dependent metabolism in XYMJ tea provides a scientific basis for time-of-day harvesting strategies and graded processing of tea products.