The PIF7 gene is a member of the bHLH family, playing a pivotal role in plant germination. However, its roles in tea plants (Camellia sinensis) remain largely unexplored. In this study, we cloned the phytochrome-interacting factor gene CsPIF7 to elucidate its role in the germination of tea plants. Subcellular localization analysis demonstrated that CsPIF7 was localized in the nucleus. Yeast one-hybrid and dual-luciferase reporter assays demonstrated that CsPIF7 directly bound to a specific region (7-321 bp) of the CsEXP promoter, thereby repressing the expression of CsEXP. These findings suggest that CsPIF7 may modulate the germination of tea plants by inhibiting the expression of CsEXP. Quantitative real-time PCR results showed that both CsPIF7 and CsEXP exhibited high expression levels in tea buds, with different expression patterns in response to abscisic acid (ABA) treatment. Furthermore, both CsPIF7 and CsEXP were upregulated under cold stress at 4 ℃, indicating their involvement in the cold response of tea plants. Taken together, these results suggest that CsPIF7 regulates CsEXP expression in an ABA-dependent manner, thereby influencing the germination of tea plants. This study provides both theoretical and experimental insights into the molecular mechanisms governing the germination of tea plants, laying the groundwork for further exploring the role of PIF7 in plant development and stress responses.
Camellia sinensis/metabolism* ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism* ; Abscisic Acid/pharmacology* ; Germination/genetics* ; Basic Helix-Loop-Helix Transcription Factors/metabolism* ; Promoter Regions, Genetic ; Cold Temperature

The epitranscriptomic mark N⁶-methyladenosine (m⁶A), which is the predominant internal modification in RNA, is important for plant responses to diverse stresses. Multiple environmental stresses caused by the tea-withering process can greatly influence the accumulation of specialized metabolites and the formation of tea flavor. However, the effects of the m⁶A-mediated regulatory mechanism on flavor-related metabolic pathways in tea leaves remain relatively uncharacterized. We performed an integrated RNA methylome and transcriptome analysis to explore the m⁶A-mediated regulatory mechanism and its effects on flavonoid and terpenoid metabolism in tea (Camellia sinensis) leaves under solar-withering conditions. Dynamic changes in global m⁶A level in tea leaves were mainly controlled by two m⁶A erasers (CsALKBH4A and CsALKBH4B) during solar-withering treatments. Differentially methylated peak-associated genes following solar-withering treatments with different shading rates were assigned to terpenoid biosynthesis and spliceosome pathways. Further analyses indicated that CsALKBH4-driven RNA demethylation can directly affect the accumulation of volatile terpenoids by mediating the stability and abundance of terpenoid biosynthesis-related transcripts and also indirectly influence the flavonoid, catechin, and theaflavin contents by triggering alternative splicing-mediated regulation. Our findings revealed a novel layer of epitranscriptomic gene regulation in tea flavor-related metabolic pathways and established a link between the m⁶A-mediated regulatory mechanism and the formation of tea flavor under solar-withering conditions.
RNA/metabolism* ; Epigenome ; Plant Proteins/metabolism* ; Plant Leaves/metabolism* ; Camellia sinensis/metabolism* ; Flavonoids ; Terpenes/metabolism* ; Tea/metabolism* ; Gene Expression Regulation, Plant

Oolong tea is a semi-fermented tea with strong flavor, which is widely favored by consumers because of its floral and fruity aroma as well as fresh and mellow taste. During the processing of oolong tea, withering is the first indispensable process for improving flavor formation. However, the molecular mechanism that affects the flavor formation of oolong tea during withering remains unclear. Transcriptome sequencing was used to analyze the difference among the fresh leaves, indoor-withered leaves and solar-withered leaves of oolong tea. A total of 10 793 differentially expressed genes were identified from the three samples. KEGG enrichment analysis showed that the differentially expressed genes were mainly involved in flavonoid synthesis, terpenoid synthesis, plant hormone signal transduction and spliceosome pathways. Subsequently, twelve differentially expressed genes and four differential splicing genes were identified from the four enrichment pathways for fluorescence quantitative PCR analysis. The results showed that the expression patterns of the selected genes during withering were consistent with the results in the transcriptome datasets. Further analysis revealed that the transcriptional inhibition of flavonoid biosynthesis-related genes, the transcriptional enhancement of terpenoid biosynthesis-related genes, as well as the jasmonic acid signal transduction and the alternative splicing mechanism jointly contributed to the flavor formation of high floral and fruity aroma and low bitterness in solar-withered leaves. The results may facilitate better understanding the molecular mechanisms of solar-withering treatment in flavor formation of oolong tea.
Camellia sinensis/genetics* ; Gene Expression Profiling ; Plant Leaves ; Plant Proteins/metabolism* ; Taste ; Tea ; Transcriptome/genetics*

Carotenoid cleavage dioxygenase (CCD) family is important for production of volatile aromatic compounds and synthesis of plant hormones. To explore the biological functions and gene expression patterns of CsCCD gene family in tea plant, genome-wide identification of CsCCD gene family was performed. The gene structures, conserved motifs, chromosome locations, protein physicochemical properties, evolutionary characteristics, interaction network and cis-acting regulatory elements were predicted and analyzed. Real time-quantitative reverse transcription PCR (RT-qPCR) was used to detect the relative expression level of CsCCD gene family members under different leaf positions and light treatments during processing. A total of 11 CsCCD gene family members, each containing exons ranging from 1 to 11 and introns ranging from 0 to 10, were identified. The average number of amino acids and molecular weight were 519 aa and 57 643.35 Da, respectively. Phylogenetic analysis showed the CsCCD gene family was clustered into 5 major groups (CCD1, CCD4, CCD7, CCD8 and NCED). The CsCCD gene family mainly contained stress response elements, hormone response elements, light response elements and multi-factor response elements, and light response elements was the most abundant (142 elements). Expression analysis showed that the expression levels of CsCCD1 and CsCCD4 in elder leaves were higher than those in younger leaves and stems. With the increase of turning over times, the expression levels of CsCCD1 and CsCCD4 decreased, while supplementary LED light strongly promoted their expression levels in the early stage. The expression level of NCED in younger leaves was higher than that in elder leaves and stems on average, and the expression trend varied in the process of turning over. NCED3 first increased and then decreased, with an expression level 15 times higher than that in fresh leaves. In the late stage of turning over, supplementary LED light significantly promoted its gene expression. In conclusion, CsCCD gene family member expressions were regulated by mechanical force and light. These understandings may help to optimize tea processing techniques and improve tea quality.
Camellia sinensis/genetics* ; Gene Expression Regulation, Plant ; Phylogeny ; Plant Leaves/genetics* ; Plant Proteins/metabolism* ; Tea

To explore the mechanism of tea albino variation and high theanine formation, 'Fuyun 6' and a new theanine-rich tea cultivar 'Fuhuang 2' were as materials in this study, pigment content, metabolome and transcriptome of the two cultivars were analyzed by ultramicroelectron microscopy, widely targeted metabolomics, targeted metabolomics and transcriptomics. The results showed that five catechins, theobromine, caffeine, and 20 free amino acids, including theanine, glutamine, arginine, etc., were identified by targeted metabolomics. The amino acid content of 'Fuhuang 2' was significantly higher than that of 'Fuyun 6', and the theanine content was as high as 57.37 mg/g in 'Fuhuang 2'. The ultrastructure of leaves showed that the chloroplast cell structure of 'Fuhuang 2' was fuzzy, most of the grana lamellae were arranged in disorder, with large gaps, and the thylakoids were filiform. The determination of pigments showed that compared with 'Fuyun 6', the contents of chlorophyll A and B, carotenoids, flavonoids and other pigments of 'Fuhuang 2' decreased significantly, some important pigment-related-genes, such as chlorophyllase (CLH), 9-cis-epoxycarotenoid dioxygenase (NCED), flavonoid 3β-hydroxylase (F3H) and flavonoid 3', 5'-hydroxylase (F3'5'H) were significantly changed. Compared with 'Fuyun 6', 'Fuhuang 2' identified 138 significantly changed metabolites (SCMs) and 658 differentially expressed genes (DEGs). KEGG enrichment analysis showed that SCMs and DEGs were significantly enriched in amino acid biosynthesis, glutathione metabolism and TCA cycle. In general, the albino phenotype of 'Fuhuang 2' may be caused by a deficiency in photosynthetic proteins, chlorophyll metabolism genes and chlorophyll content. The accumulation of high theanine in 'Fuhuang 2' may be due to the low nitrogen consumption in yellowed leaves and the lack of carbon skeleton, amino and nitrogen resources are stored more effectively, resulting in the up regulation of metabolites and related gene expression in the amino acid synthesis pathway, theanine has become a significant accumulation of nitrogen-containing compounds in yellowed leaves.
Camellia sinensis/genetics* ; Chlorophyll A/metabolism* ; Plant Proteins/genetics* ; Plant Leaves/chemistry* ; Chlorophyll/metabolism* ; Transcriptome ; Flavonoids/metabolism* ; Amino Acids/genetics* ; Tea ; Mixed Function Oxygenases/metabolism* ; Nitrogen/metabolism*

The present study was designed to determine the effects of Puer tea and green tea on blood glucose level. Male BALB/c mice were administered green tea extract (GTE) or Puer tea extract (PTE), either intragastrically or in their drinking water. The major components of these teas are epigallocatechin gallate (EGCG) and caffeine, respectively. Blood glucose measurement results showed that mice fed intragastrically or mice that drank GTE, PTE or caffeine showed significantly lower blood glucose levels compared to the control group. However, EGCG exhibited no influence on the blood glucose levels. When caffeine was eliminated from the GTE and PTE, the effect on the blood glucose levels was abolished, but the effect was recovered when caffeine was re-introduced into the extracts. Evaluation of hematological and biochemical indices at the time of the greatest caffeine-induced decrease in blood glucose levels showed that the effect of caffeine was specific. Microarray analyses were performed in 3T3-L1 preadipocytes and mature adipocytes treated with 0.1 mg · mL(-1) caffeine to identify factors that might be involved in the mechanisms underlying these effects. The results showed that few genes were changed after caffeine treatment in adipocytes, and of them only phospholipid transfer protein (PLTP) may be ralated to blood glucose. In conclusion, this study indicates that caffeine may be the key constituent of tea that decreases blood glucose levels, and it may be used to treat type 2 diabetes.
3T3-L1 Cells ; Adipocytes ; drug effects ; metabolism ; Animals ; Blood Glucose ; metabolism ; Caffeine ; pharmacology ; Camellia sinensis ; chemistry ; Hypoglycemic Agents ; pharmacology ; Male ; Mice ; Mice, Inbred BALB C ; Phospholipid Transfer Proteins ; metabolism ; Plant Extracts ; pharmacology ; Tea

AIM: (-)-Epigallocatechin-3-gallate (EGCG), a major compound of tea polyphenols, exhibited antitumor activity in previous studies. In these studies, EGCG usually inhibits EGFR, and impairs the ERK1/2 phosphorylation in tumor cells. The aim was to clarify the mechanism of ERK1/2 activation induced by EGCG. METHOD: Jurkat and 293T cells were treated with EGCG in different culture conditions. Western Blotting (WB) was employed to analyze ERK1/2 and MEK phosphorylation. Cetuximab and FR180204 were used to inhibit cell signaling. The stability of EGCG was assessed by HPLC. The concentration of hydrogen peroxide generated by the auto-oxidation of EGCG was determined by photocolorimetric analysis. RESULTS: Activation of ERK1/2 was observed to be both time-and dose-dependent. Stimulation of cell signaling was dependent on MEK activity, but independent of EGFR activity. Unexpectedly, EGCG was depleted within one hour of incubation under traditional culture conditions. Auto-oxidation of EGCG generated a high level of hydrogen peroxide in the medium. Addition of catalase and SOD to the acidic medium inhibited the oxidation of EGCG. However, this particular condition also prevented the phosphorylation of ERK1/2. The generation of ROS by hydrogen peroxide may also induce ERK1/2 activation in Jurkat cells. CONCLUSION ERK1/2 phosphorylation was caused by auto-oxidation of EGCG. Traditional culture conditions were determined to be inappropriate for EGCG research.
Camellia sinensis ; chemistry ; Catalase ; metabolism ; Catechin ; analogs & derivatives ; pharmacology ; Humans ; Hydrogen Peroxide ; metabolism ; Jurkat Cells ; MAP Kinase Signaling System ; drug effects ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Mitogen-Activated Protein Kinase 6 ; metabolism ; Oxidation-Reduction ; Phosphorylation ; Plant Extracts ; pharmacology ; Polyphenols ; pharmacology ; Superoxide Dismutase ; metabolism

Green tea, Camellia sinensis (Theaceae), a major source of flavonoids such as catechins, has recently shown multiple cardiovascular health benefits through various experimental and clinical studies. These studies suggest that green tea catechins prevent the incidence of detrimental cardiovascular events, and also lower the cardiovascular mortality rate. Catechins present in green tea have the ability to prevent atherosclerosis, hypertension, endothelial dysfunction, ischemic heart diseases, cardiomyopathy, cardiac hypertrophy and congestive heart failure by decreasing oxidative stress, preventing inflammatory events, reducing platelet aggregation and halting the proliferation of vascular smooth muscle cells. Catechins afford an anti-oxidant effect by inducing anti-oxidant enzymes, inhibiting pro-oxidant enzymes and scavenging free radicals. Catechins present anti-inflammatory activity through the inhibition of transcriptional factor NF-κB-mediated production of cytokines and adhesion molecules. Green tea catechins interfere with vascular growth factors and thus inhibit vascular smooth muscle cell proliferation, and also inhibit thrombogenesis by suppressing platelet adhesion. Additionally, catechins could protect vascular endothelial cells and enhance vascular integrity and regulate blood pressure. In this review various experimental and clinical studies suggesting the role of green tea catechins against the markers of cardiovascular disorders and the underlying mechanisms for these actions are discussed.
Animals ; Antioxidants ; administration & dosage ; Camellia sinensis ; chemistry ; Cardiovascular Diseases ; genetics ; metabolism ; prevention & control ; Catechin ; administration & dosage ; Humans ; Oxidative Stress ; drug effects ; Plant Extracts ; administration & dosage

This study investigated the acute effects of green tea extract (GTE) and its polyphenol constituents, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC), on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A (PKA) or protein kinase C (PKC) activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin (hCG), luteinizing hormone releasing hormone (LHRH), 22(R)-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22(R)-hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22(R)-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17beta-hydroxysteroid dehydrogenase function.
Androstenedione ; pharmacology ; Animals ; Camellia sinensis ; Chorionic Gonadotropin ; pharmacology ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Flavonoids ; pharmacology ; Gonadotropin-Releasing Hormone ; pharmacology ; Humans ; Leydig Cells ; drug effects ; metabolism ; Male ; Phenols ; pharmacology ; Plant Extracts ; pharmacology ; Polyphenols ; Protein Kinase C ; metabolism ; Rats ; Rats, Wistar ; Signal Transduction ; drug effects ; Testosterone ; metabolism

It is important to research the rules about accumulation and distribution of arsenic and cadmium by tea plants, which will give us some scientific ideas about how to control the contents of arsenic and cadmium in tea. In this study, by field investigation and pot trial, we found that mobility of arsenic and cadmium in tea plants was low. Most arsenic and cadmium absorbed were fixed in feeding roots and only small amount was transported to the above-ground parts. Distribution of arsenic and cadmium, based on their concentrations of unit dry matter, in tea plants grown on un-contaminated soil was in the order: feeding roots>stems approximately main roots>old leaves>young leaves. When tea plants were grown on polluted soils simulated by adding salts of these two metals, feeding roots possibly acted as a buffer and defense, and arsenic and cadmium were transported less to the above-ground parts. The concentration of cadmium in soil significantly and negatively correlated with chlorophyll content, photosynthetic rate, transpiration rate and biomass production of tea plants.
Arsenic ; metabolism ; Biomass ; Cadmium ; metabolism ; Camellia sinensis ; metabolism ; Chlorophyll ; metabolism ; Photochemistry ; Plant Shoots ; metabolism ; Tea ; metabolism