Plant Camellia Sinensis Research Articles

A CsWRKY48 Gene from Tea Plants Intercropped with Chinese Chestnut Plays an Important Role in Resistance to Biotic and Abiotic Stresses

Tea plant (Camellia sinensis) is an important horticultural crop. The quality and productivity of tea plants is always threatened by various adverse environmental factors. Numerous studies have shown that intercropping tea plants with other plants can greatly improve the quality of their products. The intercropping system of Chinese chestnut (Castanea mollissima) and tea plants is an agricultural planting model in which the two species are grown on the same piece of land following a specific spacing and cultivation method. Based on a comparative transcriptome analysis between Chinese chestnut tea intercropped plantations and a pure tea plantation, it was found that the expression levels of the WRKY genes were significantly upregulated under the intercropping pattern. In this study, we cloned a candidate gene, CsWRKY48, and verified its functions in tobacco (Nicotiana tabacum) via heterologous transformation. The contents of protective enzyme activities and osmoregulatory substances were significantly increased, and the trichomes length and density were improved in the transgenic tobacco lines. This phenotype offered an enhanced resistance to both low temperatures and aphids for transgenic lines overexpressing CsWRKY48. Further analysis indicated that the CsWRKY48 transcription factor might interact with other regulators, such as CBF, ERF, MYC, and MYB, to enhance the resistance of tea plants to biotic and abiotic stresses. These findings not only confirm the elevated resistance of tea plants under intercropping, but also indicate a potential regulatory network mediated by the WRKY transcription factor.

A defensive pathway from NAC and TCP transcription factors activates a BAHD acyltransferase for (Z)-3-hexenyl acetate biosynthesis to resist herbivore in tea plant (Camellia sinensis).

Numerous herbivore-induced plant volatiles (HIPVs) play important roles in plant defense. In tea plants (Camellia sinensis), (Z)-3-hexenyl acetate (3-HAC) has been characterized as associated with resistance to herbivores. To date, how tea plants biosynthesize and regulate 3-HAC to resist herbivores remain unclear. Based on transcriptomes assembled from Ectropis obliqua-fed leaves, a cDNA encoding BAHD acyltransferase, namely CsCHAT1, was highly induced in leaves fed with E. obliqua. Enzymatic assays showed that CsCHAT1 converted (Z)-3-hexenol into 3-HAC. Further suppression of CsCHAT1 expression reduced the accumulation of 3-HAC and lowered the resistance of tea plants to E. obliqua, while 3-HAC replenishment rescued the reduced resistance of CsCHAT1-silenced tea plants against E. obliqua. Two transcription factors (TFs), CsNAC30 and CsTCP11, were co-expressed with CsCHAT1. An integrative approach of biochemistry, DNA-protein interaction, gene silencing, and metabolic profiling revealed that the two TFs positively regulated the expression of CsCHAT1. The suppression of either one decreased the production of 3-HAC and eliminated the resistance of tea plants to E. obliqua. Notably, the suppression of either one considerably impaired JA-induced 3-HAC biosynthesis in tea plant. The proposed pathway can be targeted for innovative agro-biotechnologies protecting tea plants from damage by E. obliqua.

Deciphering the anthocyanin metabolism gene network in tea plant (Camellia sinensis) through structural equation modeling

BackgroundTea is an important cash crop that significantly contributes to rural development, poverty reduction and food security in many developing countries. It provides livelihoods for millions of smallholder producers and aids their economic stability. Anthocyanins in tea leaves provides excellent commercial quality and germplasm exploration potential. These compounds give tea leaves vibrant colors and increase health benefits. The current understanding of the synergistic regulation mechanisms responsible for color changes in purple tea, attributed to anthocyanin degradation, remains unclear.ResultsIn this study, we have identified 30 gene families within the genome that are associated to with anthocyanin metabolism from tea. These gene families play distinct roles in the biosynthesis of anthocyanin including the formation of the core, structure, modification of the molecular framework, facilitation of transport process, regulation of gene expression, breakdown pathways, sugar transportation and iron ion respectively. Subsequently, we investigated the synergistic mechanisms of anthocyanin metabolism related gene families within tea leaves using structural equation modeling. The results showed that sugar transport positively affects anthocyanin transportation, and promotes anthocyanin degradation during leaf pigmentation, whereas, it inhibits anthocyanin degradation during the fading of leaf color. Further, Iron ions facilitate the degradation of anthocyanins during their deposition and conversely, impede this degradation process during digestion. These finding suggests that tea plants may regulate the synthesis and degradation of anthocyanins through sugar transport and iron ions ensure healthy levels and vibrant colors.ConclusionsOur study contributes valuable information into the dynamic equilibrium anthocyanin mechanism and sheds light on complex regulatory mechanisms that govern the synthesis, transport and degradation of these pigments. These insights could be further used to develop strategies for enhancing anthocyanins content in unique tea germplasm to aid tea industry in producing new tea products with increased health benefits and aesthetic appeals.

Acute change in resting energy expenditure and vital signs in response to white tea consumption in females: a pilot study

BackgroundWhite tea, derived from the Camellia sinensis plant like other teas, uses tender buds and young leaves and undergoes minimal processing. This results in higher levels of antioxidants and bioactive substances, which may enhance thermogenesis more effectively than other teas. This first human study aimed to investigate the acute effects of white tea consumption on resting energy expenditure (REE) and some vital signs, including blood pressure (BP), heart rate (HR), and body temperature (BT).MethodsThirty-two healthy female volunteers with normal initial BP and whose caffeine intakes were < 300 mg/d were enrolled in the study. The caffeine and total phenolic content of white tea samples were determined by the high-performance liquid chromatography method and the Folin-Ciocalteu colorimetric method, respectively. After baseline measurements, participants consumed white tea containing 6 mg of caffeine per kilogram of lean body mass, and the white tea was prepared with bottled drinking water at 80 °C and brewed for 3 min. REE, BP, and BT were assessed at various intervals (baseline, 30 min, 120 min, and 180 min) post-consumption of the white tea.ResultsThe results revealed a significant increase in REE by 8.7% at 180 min after the consumption. In particular, there was a substantial difference in both values between the intervals of 30 min to 180 min and baseline to 180 min for REE (p < 0.05). Maximal oxygen consumption and BT also increased significantly over time (p < 0.05) and the observed increment in BT suggests a thermogenic effect associated with white tea consumption. However, systolic BP, diastolic BP, and heart rate showed no significant difference.ConclusionsThese findings suggest white tea consumption may acutely enhance REE and maximal oxygen consumption, so the results are promising for body weight management. This study is the first human study in the literature about the effects of white tea on energy expenditure and vital signs.

Ethylamine, beyond the synthetic precursor of theanine: CsCBF4-CsAlaDC module promoted ethylamine synthesis to enhance osmotic tolerance in tea plants.

The tea plant (Camellia sinensis) is a perennial green plant, and its tender leaves are rich in secondary metabolites, such as theanine. Ethylamine (EA), a small amine, is an important prerequisite for theanine synthesis. However, beyond its involvement in theanine synthesis, the other physiological functions of EA in tea plants remain unknown. In vitro experiments indicate that EA may function as scavengers of reactive oxygen species (ROS) to protect the plant against damage caused by osmotic stress. Additionally, a significant correlation between EA levels and osmotic tolerance has been observed in different tea varieties. From the results, alanine decarboxylase (CsAlaDC)-silenced tea leaves and overexpressed CsAlaDC Arabidopsis thaliana lines decreased and increased EA levels, respectively, and mediated ROS homeostasis, thus exhibiting a sensitive and tolerant phenotype. In addition, the transcription factor (TF) CsCBF4 was functionally identified, which can directly bind to the CsAlaDC promoter. CsCBF4-silenced tea leaves significantly reduced the expression levels of CsAlaDC and in turn EA content, resulting in excess ROS accumulation and an osmotic-sensitive phenotype. Taken together, these results established a new regulatory module consisting of CBF4-CsAlaDC responsible for EA accumulation and ROS homeostasis in response to osmotic stress.

The Role of Epigallocatechin Gallate (EGCG) in Treatment and Management of Sexually Transmitted Viral Infections

Tea is obtained from the young leaves and shoots of the evergreen perennial plant Camellia sinensis (L.) Kuntze, the most popular and frequently consumed product using a natural beverage worldwide. Some kinds of tea products, such as green tea, black tea, and oolong tea, have assorted flavors depending on the manufacturing techniques. Green tea has been studied for many years for its important beneficial effects, including anticancer, anti-obesity, anti-diabetes, anti-inflammatory, neuroprotective, and cardiovascular effects. These effects are primarily associated with tea polyphenols, and regular consumption has been re-ported to decrease the incidence of some chronic diseases. Current studies support that green tea catechins play an important role in healing and improving the pathology of many diseases. Epigallocatechin-3-gallate (EGCG) is the most a highly found polyphenol in the leaves and is of great interest for its protective role in the prevention of diseases. Therefore, this review presents the efficacy and possible mechanisms of EGCG against sexually transmitted viruses. Moreover, EGCG and its derivatives are recognized as safe bioactive phytochemicals for external and internal use in preventing and treating viral STIs and other concurrent infections. Multidisciplinary studies are essential to discover cheaper, safer, and more effective treat-ments using EGCG and its derivatives to improve the toxicity and formulations of viral STI medications.

Tea Administration Facilitates Immune Homeostasis by Modulating Host Microbiota.

Tea, derived from the young leaves and buds of the Camellia sinensis plant, is a popular beverage that may influence the host microbiota. Its consumption has been shown to promote the growth of beneficial bacterial species while suppressing harmful ones. Simultaneously, host bacteria metabolize tea compounds, resulting in the production of bioactive molecules. Consequently, the health benefits associated with tea may stem from both the favorable bacteria it nurtures and the metabolites produced by these microbes. The gut microbiota plays a vital role in mediating the systemic immune homeostasis linked to tea consumption, functioning through complex pathways that involve the gut-lung, gut-brain, and gut-liver axes. Recent studies have sought to establish connections between tea, its bioactive compounds, and immune regulation via the gut microbiota. In this paper, we aim to summarize the latest research findings in this field.

Metabolite profiling and transcriptome analyses reveal defense regulatory network against pink tea mite invasion in tea plant

BackgroundThe tea plant Camellia sinensis (L.) O. Kuntze is a perennial crop, invaded by diversity of insect pest species, and pink tea mite is one of the most devastating pests for sustainable tea production. However, molecular mechanism of defense responses against pink tea mites in tea is still unknown. In this study, metabolomics and transcriptome profiles of susceptible and resistant tea varieties were compared before and after pink tea mite infestation.ResultsMetabolomics analysis revealed that abundance levels of polyphenol-related compounds changed significantly before and after infestation. At the transcript level, nearly 8 GB of clean reads were obtained from each sequenced library, and a comparison of infested plants of resistant and susceptible tea varieties revealed 9402 genes with significant differential expression. An array of genes enriched in plant pathogen interaction and biosynthetic pathways of phenylpropanoids showed significant differential regulation in response to pink tea mite invasion. In particular, the functional network linkage of disease resistant proteins, phenylalanine ammonia lyase, flavanone -3-hydroxylase, hydroxycinnamoyl-CoA shikimate transferase, brassinosteroid-6-oxidase 1, and gibberellin 2 beta-dioxygenase induced dynamic defense signals to suppress prolonged pink tea mite attacks. Further integrated analyses identified a complex network of transcripts and metabolites interlinked with precursors of various flavonoids that are likely modulate resistance against to pink tea mite.ConclusionsOur results characterized the profiles of insect induced metabolic and transcript reprogramming and identified a defense regulatory network that can potentially be used to fend off pink tea mites damage.

Evaluating Native Bacillus Strains as Potential Biocontrol Agents against Tea Anthracnose Caused by Colletotrichum fructicola

Anthracnose of the tea plant (Camellia sinensis), caused by Colletotrichum spp., poses a significant threat to both the yield and quality of tea production. To address this challenge, researchers have looked to the application of endophytic bacteria as a natural alternative to the use chemical pesticides, offering potential for enhancing disease resistance and abiotic stress tolerance in tea plants. This study focused on identifying effective microbial agents to combat tea anthracnose caused by Colletotrichum fructicola. A total of 38 Bacillus-like strains were isolated from the tea rhizosphere, with 8 isolates showing substantial inhibitory effects against the mycelial growth of C. fructicola, achieving an average inhibition rate of 60.68%. Among these, strain T3 was particularly effective, with a 69.86% inhibition rate. Through morphological, physiological, and biochemical characterization, along with 16S rRNA gene phylogenetics analysis, these strains were identified as B. inaquosorum (T1 and T2), B. tequilensis (T3, T5, T7, T8, and T19), and B. spizizenii (T6). Biological and molecular assays confirmed that these strains could induce the expression of genes associated with antimicrobial compounds like iturin, fengycin, subtilosin, and alkaline protease, which effectively reduced the disease index of tea anthracnose and enhanced tea plant growth. In conclusion, this study demonstrates that B. inaquosorum, B. tequilensis, and B. spizizenii strains are promising biocontrol agents for managing tea anthracnose.

Exploring the effect of greenhouse covering cultivation on the changes of sensory quality and flavor substances of green tea

To protect tea plant (Camellia sinensis (L.) O. Kuntze) from freezing injury, plastic greenhouse covering is widely used in northern tea areas of China. Currently, there was few researches about the effect of greenhouse covering on tea quality. Our results showed greenhouse covering increased tea yield, changed leaf phenotype and decreased green tea quality. Further analysis revealed greenhouse increased the content of soluble sugars and decreased the content of EGCG and 14 amino acids. Besides, there were 223 differential volatile components were identified in green tea produced by fresh leaves with plastic greenhouse covering (GT) and green tea produced by fresh leaves without plastic greenhouse covering (TT). 81 key aroma components were contributors to the bean-like aroma of TT. 98 key aroma components contributed to the clean aroma of GT. Based on these results, the flavor wheels were constructed, providing a visual presentation of flavor between TT and GT.

Quantification of the fungal pathogen Didymella segeticola in Camellia sinensis using a DNA-based qRT-PCR assay.

The fungal pathogen Didymella segeticola causes leaf spot and leaf blight on tea plant (Camellia sinensis), leading to production losses and affecting tea quality and flavor. Accurate detection and quantification of D. segeticola growth in tea plant leaves are crucial for diagnosing disease severity or evaluating host resistance. In this study, we monitored disease progression and D. segeticola development in tea plant leaves inoculated with a GFP-expressing strain. By contrast, a DNA-based qRT-PCR analysis was employed for a more convenient and maneuverable detection of D. segeticola growth in tea leaves. This method was based on the comparison of D. segeticola-specific DNA encoding a Cys2His2-zinc-finger protein (NCBI accession number: OR987684) in relation to tea plant Cs18S rDNA1. Unlike ITS and TUB2 sequences, this specific DNA was only amplified in D. segeticola isolates, not in other tea plant pathogens. This assay is also applicable for detecting D. segeticola during interactions with various tea cultivars. Among the five cultivars tested, 'Zhongcha102' (ZC102) and 'Fuding-dabaicha' (FDDB) were more susceptible to D. segeticola compared with 'Longjing43' (LJ43), 'Zhongcha108' (ZC108), and 'Zhongcha302' (ZC302). Different D. segeticola isolates also exhibited varying levels of aggressiveness towards LJ43. In conclusion, the DNA-based qRT-PCR analysis is highly sensitive, convenient, and effective method for quantifying D. segeticola growth in tea plant. This technique can be used to diagnose the severity of tea leaf spot and blight or to evaluate tea plant resistance to this pathogen.

The Serine Acetyltransferase (SAT) Gene Family in Tea Plant (Camellia sinensis): Identification, Classification and Expression Analysis under Salt Stress.

Cysteine plays a pivotal role in the sulfur metabolism network of plants, intimately influencing the conversion rate of organic sulfur and the plant's capacity to withstand abiotic stresses. In tea plants, the serine acetyltransferase (SAT) genes emerge as a crucial regulator of cysteine metabolism, albeit with a notable lack of comprehensive research. Utilizing Hidden Markov Models, we identified seven CssSATs genes within the tea plant genome. The results of the bioinformatics analysis indicate that these genes exhibit an average molecular weight of 33.22 kD and cluster into three distinct groups. Regarding gene structure, CssSAT1 stands out with ten exons, significantly more than its family members. In the promoter regions, cis-acting elements associated with environmental responsiveness and hormone induction predominate, accounting for 34.4% and 53.1%, respectively. Transcriptome data revealed intricate expression dynamics of CssSATs under various stress conditions (e.g., PEG, NaCl, Cold, MeJA) and their tissue-specific expression patterns in tea plants. Notably, qRT-PCR analysis indicated that under salt stress, CssSAT1 and CssSAT3 expression levels markedly increased, whereas CssSAT2 displayed a downregulatory trend. Furthermore, we cloned CssSAT1-CssSAT3 genes and constructed corresponding prokaryotic expression vectors. The resultant recombinant proteins, upon induction, significantly enhanced the NaCl tolerance of Escherichia coli BL21, suggesting the potential application of CssSATs in bolstering plant stress resistance. These findings have enriched our comprehension of the multifaceted roles played by CssSATs genes in stress tolerance mechanisms, laying a theoretical groundwork for future scientific endeavors and research pursuits.

Tea Consumption and Human Health: A Review of Benefits and Impact on Chronic Disease Prevention

Tea, derived from the Camellia sinensis plant, is a globally consumed beverage with a rich history spanning thousands of years. Its cultural and social significance is evident in numerous societies, from ancient China to modern Western cultures. Historically revered for its potential health benefits, tea has gained scientific support for its role in chronic disease prevention. This review examines the historical and cultural importance of tea, its bioactive compounds, and its impact on health. Key areas include cancer prevention, cardiovascular health, metabolic syndrome management, and neuroprotection. Green tea, particularly noted for its high concentration of catechins, has been extensively studied for its health-promoting effects, including antioxidant, anti-inflammatory, and cancer-preventive properties. Black, oolong, and white teas each offer distinct benefits due to their unique compositions. Despite the promising evidence, potential risks such as caffeine sensitivity and reduced iron absorption should be considered. Future research is needed to further elucidate the mechanisms underlying tea’s health benefits and to explore its efficacy across diverse populations. Keywords: Tea, Camellia sinensis, Health Benefits, Cancer Prevention, Cardiovascular Health, Metabolic Syndrome.

Genome-wide analysis of the HD-Zip IV gene family in Camellia sinensis and functional characterization of CsHDZIV3 under trichome development

The HD-Zip IV transcription factors, which belong to the homeodomain leucine zipper (HD-ZIP) family, are essential for the development of epidermal cells in plants. However, there is limited information about HD-Zip IV in tea plant (Camellia sinensis L.). Here we identified 10 HD-Zip IV members (CsHDZIV1∼10) in tea plant, which are distributed in 8 chromosomes with two segmentally duplicated gene pairs. The exon number of CsHDZIVs ranges from 9 to 11, with most genes having two conserved motifs in the 3’UTR. CsHDZIV1∼9 have almost identical motifs and tertiary structures. The promoter region of CsHDZIVs was predicted to harbor light, phytohormone, stress, growth and developmental elements. 9 CsHDZIVs are divided into 5 subfamilies and located in the nucleus. They exhibited expression trends across 12 tea plant tissues and responded to PEG, cold, NaCl and shading treatments. CsHDZIV3 overexpression partially and completely restored trichome development defects of gl2 leaves and stems, respectively. CsHDZIV3 showed histochemical staining in Arabidopsis trichomes and protein interaction with itself. It might regulate trichome development through forming homodimers. These findings contribute to functional study of tea plant HD-Zip IV and provide guiding significance for the investigation of trichome development and the improvement of trichome traits.

Active components and skin care properties of tea seed oil from Camellia sinensis

In China, many tea seeds, the ripe seeds of the tea plant (Camellia sinensis (L.) O. Kuntze), are discarded as agricultural waste. Therefore, the tea seed oil that could have been obtained from tea seeds has also been wasted. To fully understand the content and efficacy of the main active ingredients in tea seed oil (TSO), the chemical composition and activity characteristics of TSO in different areas of Guizhou, China were investigated. The results demonstrated that TSO had high content of unsaturated fatty acids (UFA) and good skincare properties, such as anti-oxidation, anti-ultraviolet, moisturizing, whitening, and bacteriostasis. Furthermore, TSO showed a scavenging effect on reactive oxygen species in mouse fibroblasts cells (L929) and rat cardiomyocytes cells (H9C2). TSO exhibited high biocompatibility and promoted the proliferation and migration of L929. Southwest Guizhou (T4) and southern Guizhou (T6) might be used as high-quality producing areas for cosmetic oil by the weight analysis of each indicator. In summary, as the main producing area of tea in the world, this study helps to alleviate the problem of low oil self-sufficiency in China. The work offers a scientific basis for the in-depth development of TSO, especially in the field of skin care.

Improving carbon flux estimation in tea plantation ecosystems: A machine learning ensemble approach

Tea plant (Camellia sinensis) is a major global crop consumed as a drink after water. Quantifying carbon flux, specifically the net ecosystem exchange (NEE), in tea plantations is essential for determining carbon sequestration and ecosystem carbon balance. The Eddy covariance (EC) system is widely used for continuous monitoring of carbon flux but high costs associated with installation and maintenance limit its widespread adoption. In addition, EC flux data is often discarded due to malfunction of instruments caused by adverse weather conditions. Therefore, additional approaches for estimating NEE are necessary to overcome these challenges and ensure accurate NEE measurement. For this purpose, three standalone tree-based machine learning (ML) models were used for NEE estimation using EC flux data collected from tea ecosystem located in subtropical region (Danyang county of Zhenjiang city) of China. To address the accuracy limitations inherent in standalone ML models, the ensemble mechanism based on voting regressor method was proposed. In addition, k-fold cross-validation based on early stopping process was also used to enhance the performance of standalone ML models. Based on visual plots (scatter diagram, heatMap, Taylor diagram) and performing indices (root-mean-square error (RMSE), determination coefficient (R2), mean absolute error (MAE), mean absolute percentage error (MAPE), Nash–Sutcliffe efficiency (NSE), correlation coefficient (r), Kling Gupta Efficiency (KGE) and index of agreement (d)), the findings indicated that non-linear ensemble-generalized regression neural network (NLE-GRNN) significantly improved standalone ML model's results. In current study, the highest NSE, r and d in case of standalone ML model (DT) achieved 0.49, 0.73 and 0.75 respectively while our proposed NLE-GRNN model improved 48 % in NSE value (NSE = 0.97), 25 % in r value (r = 0.98) and 24 % in d value (d = 0.99). Likewise, NLE-GRNN significantly reduce errors (MAE, MAPE and RMSE) and provides NEE estimate closet to the observed value. The impact of climatic variables on NEE using shapley additive explanations (SHAP) analysis revealed that Rg (solar radiation) and Tair (air temperature) were the prime factors controlling NEE variation in the tea ecosystem. Considering the high accuracy and stability of the studied ML models, it is recommended to apply developed ensemble ML model (NLE-GRNN) for significant improvement of NEE estimate in the tea biomes or other ecosystems.

Molecular responses reveal that two glutathione S-transferase CsGSTU8s contribute to detoxification of glyphosate in tea plants (Camellia sinensis)

Tea plant (Camellia sinensis) is an important economical crop that frequently suffers from various herbicides, especially glyphosate. However, the molecular responses and regulatory mechanisms of glyphosate stress in tea plants remain poorly understood. Here, we reported a transcriptome dataset and identified large number of differentially expressed genes (DEGs) under glyphosate exposure. Next, two glutathione S-transferase genes (CsGSTU8–1 and CsGSTU8–2) that upregulated significantly were screened as candidate genes. Tissue-specific expression patterns showed that both CsGSTU8–1 and CsGSTU8–2 had extremely high expression levels in the roots and were predominantly localized in the nucleus and plasma membrane based on subcellular localization. Both were significantly upregulated at different time points under various stressors, including drought, cold, salt, pathogen infections, and SA treatments. An enzymatic activity assay showed that CsGSTU8–1 catalyzes the conjugation of glutathione with 2,4-dinitrochlorobenzene (CDNB). Functional analysis in yeast verified that the two genes significantly contributed to the detoxification of glyphosate, and CsGSTU8–1 had a stronger role in detoxification than CsGSTU8–2. Taken together, these findings provide insights into the molecular responses of tea plants to glyphosate and the functions of CsGSTU8s in glyphosate detoxification, which can be used as a promising genetic resource for improving herbicide resistance in tea cultivars.

Insight into the fate of tolfenpyrad in tea plant (Camellia sinensis L.) from root uptake

Residual pesticides in agricultural environments, including soil and irrigation water, can be taken up by plants, and thus pose a potential risk to food safety. Although tolfenpyrad has been widely used in tea plantations, limited information is available on its root uptake and fate in tea plants (Camellia sinensis L.). Exploring the mechanisms involved is crucial for understanding the migration and accumulation of tolfenpyrad in tea plants, particularly in the edible parts. In this study, root uptake of tolfenpyrad and its subsequent translocation, distribution, and metabolism in tea seedlings were investigated. The results indicated that the passive transport and apoplastic pathway dominated the root uptake of tolfenpyrad. After uptake, tolfenpyrad distributed predominantly in the cell walls (90.8–92.0 %) of roots, resulting in limited upward translocation in water-soluble fractions through transpirational pull, with translocation factor values far <1 (TFstem/root = 0.115–0.453 and TFleaf/stem = 0.039–0.184). Similar accumulation patterns were observed for the carboxylated metabolite PT-CA as well as hydroxylated metabolite PT-OH. Interestingly, the subcellular distribution of PT-CA in stems was much different from that of the parent tolfenpyrad: PT-CA mainly distributed in the stem cell walls (41.72 %) and cell organelles (56.18 %) at 3 h, then gradually transferred into the cell-soluble fractions (33.07 %) after 120 h. Results from the present study indicated limited upward translocation of tolfenpyrad with its main metabolites to leaves. This finding helps to alleviate concerns about environmental residual tolfenpyrad in tea consumption and provides valuable information for the safety evaluation of tolfenpyrad.

Physiological and metabolomic analyses reveal the resistance response mechanism to tea aphid infestation in new shoots of tea plants (Camellia sinensis)

The tea plant (Camellia sinensis (L.) O. Kuntze) is an important woody economic crop and often attacked by various insect pests such as tea aphids (Toxoptera aurantii Boyer de Fonscolombe). To reveal tea plant responses to tea aphid infestation, tea aphid-resistant cultivar ‘Taicha13’ and -susceptible one ‘Jingfeng’ were first screened, and then widely targeted metabolomics profiling, biochemical parameter and RT-qPCR analyses were performed in three samples, TCN (tea aphid non-infested ‘Taicha13’), JFN (tea aphid non-infested ‘Jingfeng’) and JFA (tea aphid-infested ‘Jingfeng’). The results showed amnio acid (plus proline) and protein content, and amnio acid: sucrose ratio were significantly less abundant in TCN relative to JFN, suggesting TCN is low nutritional quality for tea aphids. Metabolite profiling revealed that flavonoids and JA-isoleucine (JA-Ile) were more enriched in TCN and JFA compared to JFN, proposing effective roles of flavonoids and JA-Ile in tea plant defense against tea aphid infestation. RT-qPCR results demonstrated that five JA biosynthesis genes (CsLOX2, CsLOX3, CsOPR, CsAOC and CsJAR) in exception of CsAOS, and six flavonoid biosynthesis genes (CsPAL, CsC4H, CsCHS1, CsCHS2, CsFL and CsDFR) shared similarly higher abundance in TCN than in JFN, and exhibited elevated expression levels in JFA relative to JFN, further suggesting flavonoids and JA confer tea plant resistance against tea aphid feeding. Overall, our findings uncovered that tea aphid-infestation activated defensive responses and highlighted involvement of nutritional quality, flavonoids and JA-Ile in tea plant resistance against tea aphid infestation.

Effects of catechin on the malignant biological behavior of gastric cancer cells through the PI3K/Akt signaling pathway

Catechin is a kind of flavonoids, mainly derived from the plant Camellia sinensis. It has a strong antioxidant effect, and it also has significant therapeutic effects on anti-cancer, anti-diabetes, and anti-infection. This study was intended to look at how catechin affected the malignant biological activity of gastric cancer cells. We used databases to predict the targets of catechin and the pathogenic targets of gastric cancer. Venn diagram was used to find the intersection genes, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses were performed on intersection genes. Using the STRING database, the Protein-Protein Interaction (PPI) network was built. The top 8 genes were screened by Cytoscape 3.9.1, then their binding was verified by molecular docking. The proliferation ability, cell cycle, apoptosis and migration of gastric cancer cells were detected, as well as the protein expression levels of PI3K, p-AKT, and AKT and the mRNA expression levels of AKT1, VEGFA, EGFR, HRAS, and HSP90AA1 in gastric cancer cells. Our research revealed that different concentrations of catechin could effectively inhibit the proliferation and migration of gastric cancer cells, regulate the cell cycle, and promote the death of these cells, and it's possible that the PI3K/Akt pathway was crucial in mediating this impact. Moreover, adding the PI3K/Akt pathway agonist significantly reduced the promoting effect of catechin on the apoptosis of gastric cancer cells. This study suggested that catechin was a potential drug for the treatment of gastric cancer.