As the primary reproductive organ of the tea plant (Camellia sinensis), the flower exhibits rich phenotypic diversity, which holds significant importance for the genetic improvement of tea varieties. In this study, 64 tea germplasm accessions were used to systematically investigate the phenotypic diversity of nine qualitative traits and twelve quantitative traits related to floral morphology. Based on 47 111 high-quality SNP markers, population genetic structure analysis and genome-wide association study (GWAS) were performed. The results revealed abundant genetic diversity in floral traits among the tested materials, with ovary villi, weight per 100 flowers, and the proportion of the bifurcation to the columella showing relatively large variation, which could serve as core evaluation indicators. Population structure analysis divided the materials into three genetic subgroups, which were highly consistent with the phenotypic clustering results. Through GWAS, 273 SNP loci significantly associated with 10 important floral traits were identified. Furthermore, five core candidate genes (GWHTASIV003067, GWHTASIV018433, GWHTASIV032688, GWHTASIV001183, GWHTASIV044042) were screened, which are involved in key biological processes such as growth regulation, RNA editing, cell cycle control, chromatin remodeling, and transcriptional regulation. This study provides, for the first time, a systematic multidimensional analysis of the genetic basis of floral traits in tea plants, offering important gene resources and a theoretical foundation for research into the molecular mechanisms of floral traits and for molecular marker-assisted breeding in tea plant.

The aging process is inevitably accompanied by a decline in muscle strength and mass, severely impairing the health and quality of life of the elderly population. Epicatechin (EC) is one of the main secondary metabolites found in tea, possesses a variety of biological activities. Previous studies have revealed the anti-aging effects of EC, but its relationship with age-related sarcopenia remains unclear. To investigate the effects and underlying mechanisms of EC on age-related sarcopenia, this study employed naturally aged C57BL/6J mice as a model. A comprehensive evaluation was conducted using a series of methodologies, including animal behavioral tests, muscle index measurements, histological analysis, Elisa assays, transcriptome sequencing and RT-qPCR validation. The results show that compared with the control group, EC treatment significantly improved the grip strength and endurance performance of aged mice (P＜0.05), and significantly increased the muscle index of the gastrocnemius, tibialis anterior, and quadriceps femoris muscles (P＜0.05). The gastrocnemius muscle fibers in the EC treated group were larger in area and more regularly arranged. EC significantly reduced the levels of the inflammatory factors IL6 and TNFα in aged mice (P＜0.05). Further transcriptomic sequencing and RT-qPCR validation reveal that EC might downregulate the expression of the BCAA transaminase gene BCAT1 and upregulate the expression of the BCAA transaminase gene BCAT2, as well as the BCAA transporter genes LAT1 and LAT2, thereby regulating muscle protein synthesis. Meanwhile, it could upregulate the expressions of skeletal muscle differentiation-related genes including MyoD, MyoG, MRF4, MCK and Myf5 to alleviate sarcopenia in aged mice.

Methylated catechins exhibit significant physiological activities, such as anti-allergy effects, and demonstrate stronger stability and higher oral absorption rate than unmethylated catechins. However, tea germplasms rich in methylated catechins are relatively rare. This study measured the EGCG3′′Me content in 447 tea germplasms from different regions with extensive genetic backgrounds, and two unique tea germplasms with high EGCG3′′Me content, namely ‘Jinxiu 2-2’ (JX) and ‘Pinming Tea’ (PM), were found. The tea germplasms JX, PM, and ‘Hongfugui’ (BFK) with high EGCG3′′Me content, as well as ‘Shuchazao’ (SCZ) with EGCG3′′Me content below the detection limit, were used as research materials. Relative expression levels of flavonol and anthocyanin O-methyltransferase (CsFAOMT1) in JX, PM, and BFK were significantly higher than that in SCZ. Further analysis reveals that four types of CsFAOMT1 alleles were cloned from the four tea germplasms, and all of them contain CsFAOMT1.3. Enzyme activity analysis at the protein level reveals that the CsFAOMT1 protein activities in the three tea germplasms with high EGCG3′′Me content all exhibit high activity with minimal differences between them. These results indicate that JX and PM can enrich EGCG3′′Me due to their high expression levels of CsFAOMT1. This study identified tea germplasm with high EGCG3′′Me content and elucidated the molecular mechanisms underlying its unique traits, providing important materials and theoretical basis for breeding new tea cultivars with high methylated catechin content.

During the growth and development of tea plants (Camellia sinensis), abiotic stresses such as drought and salinity frequently occur, causing significant adverse effects on tea yield and quality. This study focused on the tea phospholipid: diacylglycerol acyltransferase 1 (PDAT1) gene and systematically investigated its function in response to abiotic stresses through bioinformatics analysis, gene expression pattern detection, and transgenic functional verification. Bioinformatics analysis reveals that the protein encoded by the CsPDAT1 gene possesses a typical lysophospholipid acyltransferase (lysoPLA) domain. Real-time quantitative PCR (qRT-PCR) results demonstrats that the expression of the CsPDAT1 gene was significantly upregulated under drought and high-salt treatments, particularly during the early stages of drought stress. To further elucidate its function, researchers constructed an overexpression vector for the CsPDAT1 gene and transformed it into Arabidopsis thaliana. Finally three homozygous T3-generation transgenic lines were obtained. Phenotypic analysis reveals that under drought stress, Arabidopsis plants overexpressing the CsPDAT1 gene exhibited a significantly higher seed germination rate compared to that of wild-type plants, along with reduced malondialdehyde (MDA) content, increased proline content, and significantly enhanced antioxidant enzyme activity. This study confirmed that the CsPDAT1 gene in tea plants enhances plant tolerance to abiotic stress by regulating cell membrane lipid metabolism and the accumulation of osmoprotectants, providing a theoretical foundation and genetic resources for stress-resistant molecular breeding in tea plants.

‘Huangjincha’ is a tradtional and local tea germplasm resource in Xiangxi, with an excellent flavor quality, especially its obvious aroma characteristics, which is highly favored by consumers. This study selected four tea cultivars, namely ‘Baojing Huangjincha 1’, ‘Huangjincha 2’, ‘Huangjincha 8’, ‘Huangjincha 18’, to produce ‘Huangjincha’ green and black tea samples. Sensory evaluation, gas chromatography-mass spectrometry (GC-MS), and relative odor activity value (ROAV) were used to analyze their aroma components. The results show that ‘Huangjincha’ green tea is characterized by its fresh and elegant aroma and a refreshing, sweet aftertaste, while ‘Huangjincha’ black tea exhibits distinct sweet and floral notes. A total of 101 volatile aroma compounds were detected in ‘Huangjincha’ green tea. Among these, esters and alcohols accounted for 34.4% to 53.5% and 21.9% to 36.3%, respectively. A total of 140 volatile aroma compounds were detected in ‘Huangjincha’ black tea, with alcohols, esters, and aldehydes being the main volatile components, accounting for 38.6% to 60.0%, 11.0% to 26.9%, and 9.7% to 17.8%, respectively. The primary aroma-contributing compounds of both ‘Huangjincha’ green and black tea were further screened. A total of 20 compounds were identified as key contributors to the aroma of ‘Huangjincha’ green tea, including linalool, 3,5-octadien-2-one, cis-jasmone, β-ionone, lauric acid, β-cyclocitral, and 2-pentylfuran. For ‘Huangjincha’ black tea, 33 shared key aroma components compounds were identified, including linalool, benzaldehyde, 3,5-octadien-2-one, trans-β-ionone, (Z)-linalool oxide (furanoid) and 4-heptenal. This study had preliminarily revealed the similarities and differences in aroma quality characteristics and chemical composition in ‘Huangjincha’ green and black tea made by different cultivars, which could be used to improve the processing technology system of ‘Huangjincha’.

The seeds of ancient tea plants represent valuable natural genetic resources and gene pools, playing a crucial role in enriching tea plant genetic resources and maintaining genetic diversity. To investigate their characteristics, this study utilized seeds from 8 ancient tea plants (designated TZ-1 to TZ-8) and a locally cultivated tea plant (TZ-9) in Tongzi County, Guizhou Province, China. We systematically compared their biological properties, including morphology, 100-grain weight, water absorption rate, bulk density, germination rate, and tea saponin content. Additionally, we analyzed the endophytic bacterial diversity using high-throughput sequencing. The results reveal significant variations in the biological properties among the ancient tea seeds. Specifically, TZ-3 exhibited the highest 100-grain weight (269.52 g), while TZ-1 had the smallest values in these traits. The cultivated variety TZ-9 has the highest relative water absorption rate (32%) and germination rate (85%). Among the ancient tea plants, TZ-6 had the highest germination rate (76%), and TZ-2 had the lowest (11.67%). The tea saponin content varied from 21.00% to 49.91% among the ancient tea plants, with TZ-3 and TZ-4 exceeding 40%. The analysis of endophytic bacteria detects a total of 1 141 OTUs, covering 26 bacterial phyla. Among them, the richness of the TZ-3 community was the highest (OTU=185), and TZ-2 was the lowest (OTU=46). PCoA/NMDS analysis shows that the community structures of TZ-2, TZ-3, and TZ-8 were significantly separated, and this separation was independent of the ecological type (ancient/cultivated plants). Correlation analysis revealed that the abundance of genera such as Planctomycetota and Firmicutes was positively correlated with seed diameter, 100-grain weight, and tea saponin content (P<0.05), while Desulfobacterota and Bacteroidota were negatively correlated with water absorption rate. This study initially elucidated the association between the biological characteristics of ancient tea seeds and their endophytic bacterial communities, offering a theoretical foundation for the conservation and innovative utilization of tea germplasm resources.

The growing environment significantly influences the accumulation of chemical compounds in tea plants. However, systematic studies on the changes in chemical composition after translocating the tea cultivar ‘Huangshanzhong’ to the high-latitude Shandong region remain scarce. This study investigated the green tea samples of Camellia sinensis cv. Huangshanzhong from two regions: the native origin (YCD, Huangshan, Anhui) and a transplanted region (SD, Rizhao, Shandong). Differences in the content levels of the chemical components were analyzed. Additionally, widely-targeted metabolomics techniques were employed to identify differential metabolites and elucidate core metabolic pathways. The results demonstrate that SD samples exhibited significantly higher levels of water-soluble carbohydrates, total ash, water-soluble ash, water extract content and total galloylated catechins than YCD. While the total polyphenols and caffeine showed no inter-regional difference. SD accumulated more asparagine, glutamate, and arginine, whereas YCD was richer in flavor-related amino acids, such as theanine, GABA, lysine. Metabolomics analysis identified 116 differential metabolites (73 upregulated, 43 downregulated), with flavonoids exhibiting the highest abundance and diversity among them. KEGG enrichment analysis further revealed that the purine metabolism, phenylalanine metabolism, and pyrimidine metabolism pathways were the most significantly enriched pathways, contributing most to the differences between the SD and YCD samples. This study provided a systematic comparison of chemical components in green tea from cv. ‘Huangshanzhong’ after high-latitude transplantation versus the original cultivation, offering scientific insights into tea cultivar adaptation and flavor quality optimization.

Processing techniques significantly alter the accumulation and composition of internal components in tea, forming different categories of tea products. Currently, there is limited research on the accumulation of compounds in different categories of Jingshan tea and their impact on taste quality characteristics. In this study, Jingshan green tea, matcha, and black tea were selected as the research object. The contents of physicochemical components such as water extracts, tea polyphenols, amino acids, and caffeine were detected, and the main compounds that constitute the taste and aroma skeleton of Jingshan tea were analyzed. The results show that the contents of compounds related to taste, such as water extracts, tea polyphenols, theanine, and glutamic acid, were significantly higher in green tea than in black tea. Meanwhile, black tea exhibited the highest accumulation of γ-aminobutyric acid. Jingshan green tea, matcha, and black tea were characterized by their “rich floral aroma and refreshing sweetness”, “fresh and thick”, and “sweet fruit aroma and lingering sweetness”, respectively. A total of 101 volatile compounds were identified in different categories of tea samples (31 in green tea, 30 in matcha, and 40 in black tea), among which cis-jasmone and 4,8-dimethyl-1,3,7-nonatriene are the key components contributing to the “elegant and floral” aroma quality of green tea. β-ionone, α-ionone, and β-cyclocitral are the essential components for the “fragrance” aroma of matcha. Geraniol and methyl salicylate are the crucial components for the “sweet aroma” of black tea. The research findings would be beneficial for expanding the study of Jingshan tea's flavor chemistry and provided a valuable reference for enhancing the high-quality processing of Jingshan tea.

This study aimed to elucidate the underlying mechanism by which roasting temperatures influence the flavor quality of Wuyi Rougui tea. Specifically, it sought to characterize the dynamic responses of biochemical components, antioxidant activity, and spectral features under varying thermal processing conditions. Wuyi Rougui tea leaves were processed at three roasting temperatures: (light roast 110 ℃, medium roast 125 ℃, high roast 140 ℃). A comprehensive analytical framework was implemented, integrating sensory evaluation, chromaticity analysis, ultra-high-performance liquid chromatography (UHPLC)-based quantification, and in vitro antioxidant capacity assessment. Fourier transform infrared spectroscopy (FTIR) coupled with chemometric modeling was employed. Raw spectral data were preprocessed to establish an orthogonal partial least squares-discriminant analysis (OPLS-DA) model for identifying characteristic wave numbers. Subsequent correlation analysis and partial least squares regression (PLSR) modeling reveal the relationships between spectral signatures and quality attributes (sensory parameters, chromaticity indices, biochemical constituents, and antioxidant activity). This ultimately identified the key compounds governing roasting-derived flavor profiles. The roasting temperature significantly modulated non-volatile metabolites and antioxidant capacity. Medium-fire-treated samples exhibited optimal sensory quality with a mellow taste profile. Elevated roasting temperatures progressively reduced tea polyphenols (TP), free amino acids (FAA), total flavonoids (TF), soluble total sugars (STS), catechin content, and DPPH radical scavenging capacity. The FTIR-OPLS-DA modeling (R²X=0.964, R²Y=0.991, Q²=0.981) identified two discriminative wave numbers: 1 018 cm^-1 (C-O-C vibration in carbohydrates) and 1 739 cm^-1 (The C=O bond of the ester is broken), which strongly correlated with taste attributes (|r|>0.69). The PLSR analysis further identified soluble sugars, FAA, ferulic acid, and chlorogenic acid as critical determinants of roasting flavor (R2 p>0.85). This study is the first to elucidate the synergistic interplay of soluble sugars, FAA, epicatechin derivatives (EGCG/EGC/EC), and phenolic acids (ferulic acid/CGA) in shaping the characteristic roasting quality of Wuyi Rougui tea. The findings established a theoretical foundation for precise roasting in Wuyi rock tea production and proposed a novel spectroscopy-guided quality control strategy.

In recent years, tea production in China has faced challenges of labor shortages, driving urgent industrial demands for mechanized harvesting technologies. The prevalent issues of high leaf fragmentation and low harvest quality in current mechanical systems are closely related to tea plant phenotypic traits. This study investigated seven widely cultivated tea cultivars mainly being suitable for black/oolong tea production in Guangdong Province. Phenotypic data from 100 quadrat sample plots of seven tea cultivars was systematically collected. Multiple analytical approaches, combined with mechanical harvesting quality predictive models, were employed to identify critical determining traits. The correlation analysis demonstrates that leaf length, leaf length-to-width ratio, length of one bud with two leaves, and length of one bud with three leaves were positively correlated with mechanical harvesting quality, whereas the total bud density showed a negative correlation. Grey relational analysis reveals significant associations between the mechanical harvesting quality and the leaf length-to-width ratio, leaf width, length of one bud with one leaf, and length of one bud with two leaves. Random forest analysis identifies the leaf length-to-width ratio, third internode length, and fourth internode length as critical traits influencing the superior harvest rate, intact rate, and fragmentation rate in mechanical harvesting, respectively. Further validation combined four phenotypic trait groups (full trait set, correlation-significant traits, grey relational>0.9, random forest top 6) with four machine learning algorithms to predict three core mechanical harvesting traits. The results demonstrate the grey relational traits achieved the optimal prediction for superior harvest rate (R²=0.65, RMSE=0.04), and random forest-selected traits were suitable for intact rate prediction (R²=0.86, RMSE=0.02), and complete trait group shows the highest fragmentation rate accuracy (R²=0.92, RMSE=0.01). Integrated modeling analysis identifies the length of one bud with two leaves and third internode length as key mechanical harvestable traits influencing black and oolong tea production. These findings established theoretical foundations and provided critical parameters for breeding tea cultivars optimized for mechanical harvesting.

Eotetranychus kankitus is an agricultural pest mite that damages many crops. Conducting mitochondrial genome analysis can clarify its structural characteristics and the phylogenetic relationships among species in the family of Tetranychidae species. The mitochondrial genome sequences of E. kankitus on pomelo and tea plants were obtained by PCR amplification, sequencing, assembly and annotation. The phylogenetic tree of Tetranychidae was constructed based on 13 protein-coding genes and 2 rRNA gene sequences by maximum likelihood and Bayesian methods. The mitochondrial genomes of E. kankitus on pomelo and tea plants were both in size of 13 032 bp, with GenBank accession numbers OQ955767 and OQ955768, respectively. Both the two mitochondrial genomes included 13 protein coding genes, 2 rRNA genes, 22 tRNA genes and a 40 bp control region, with a consistent gene arrangement. The sequence similarity rate of the two mitochondrial genomes was high, and base composition values of the whole genome and each region were close. E. kankitus on both hosts clustered into one branch in the phylogenetic tree, and the genetic distance between them was 0.068 0, which was much smaller than that between E. kankitus and other mites in Tetranychidae. A close relationship was showed between E. kankitus and Panonychus species in both genetic distance and phylogenetic analysis. According to analyses of mitochondrial genomes, the differentiation degree of E. kankitus on pomelo and tea plants was low, and the risk of transference between the two hosts was high. It is recommended that tea gardens with E. kankitus and surrounding citrus crops should strengthen field monitoring work.

The indoor efficacy of eight chemical pesticides and six biological pesticides against Basilepta melanopus adult was evaluated using the leaf-dipping method. Field control efficacy trials were conducted to screen the pesticides for controlling B. melanopus adult, and the residues of these pesticides in dry tea were measured seven days after application. The results show that in the indoor efficacy test, 72 h after I-cyhalothrin (effective component 16.5 mg·L^-1), bifenthrin (effective component 55.6 mg·L^-1), chlorfenapyr (effective component 143 mg·L^-1), thiacloprid (effective component 124 mg·L^-1), tolfenpyrad (effective component 165 mg·L^-1), pyriproxyfen-chlorfenapyr (effective component 165 mg·L^-1) and natural pyrethrum (effective component 52.8 mg·L^-1) had higher lethality to the adult of B. melanopus, with lethality rates of 100%, 100%, 100%, 100%, 100%, 95% and 80%, respectively. Next were pyriproxyfen (effective component 1 480 mg·L^-1) and azadirachtin (effective component 16.5 mg·L^-1), with the lethality rates of 50% and 28%. The lethality rates of buprofezin, Empedobacter brevis, tea saponin, cineole, Metarhizium anisopliae CQMa421 were not significantly different from the clear water control. The maximum control efficacies of I-cyhalothrin (effective component 16.88 g·hm^-2), bifenthrin (effective component 56.25 g·hm^-2), chlorfenapyr (effective component 201 g·hm^-2), and natural pyrethrum (effective component 36 g·hm^-2) against B. melanopus adult after field application for 1~7 d were up to 100%, 100%, 93.99% and 40.82%, respectively. After 7 days of pesticide application, the residues of bifenthrin and chlorfenapyr were both lower than the maximum residue limits (MRL) in national standard (GB 2763—2021) and EU standard for pesticides in tea. Whereas the residue of I-cyhalothrin was only lower than the MRL in GB 2763—2021. Although the field control efficacy of thiacloprid (effective component 126 g·hm^-2) could be 98.31%, the residue in dry tea produced 7 days after application exceeded the MRLs in both GB 2763—2021 and EU standards. In conclusion, bifenthrin, chlorfenapyr, I-cyhalothrin and natural pyrethrum can be selected as needed for the control of B. melanopus adult in tea plantations.

Tea gray blight is one of the major foliar diseases in tea plantations, significantly affecting both yield and quality. In July 2023, tea leaves exhibiting resembling gray blight symptoms were observed during a filed surver in tea plantations in Mengla County, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province. As the causal pathogen of these symptoms had not been previously reported in this region, this study aimed to identify the causal agent and its taxonomic classification. The pathogen was successfully isolated and identified using a combination of tissue isolation, pathogenicity testing via wound inoculation, morphological characterization, and molecular phylogenetic analysis based on ITS and TUB genes squences. The results confirmed that the strain FN3-2, isolated from symptomatic leaves, was pathogenic. Based on morphological traits and molecular evidence, the pathogen was finally identified as Neopestalotiopsis protearum. The finding provided a scientific basis for the accurate disease diagnosis and biocontrol agent screening, contributing to the sustainable development of tea production in the region.

The tea geometrid (Ectropis grisescens Warren) is the most destructive defoliator in tea gardens in China. In recent years, E. grisescens has developed medium to high level resistance against common pesticides. To address this challenge, six chemical pesticides and three biological pesticides were selected and comprehensively evaluated from four aspects: laboratory toxicity assays, field evaluation, safety assessment for natural enemies, and pesticide residue analysis in tea leaves. The results of laboratory toxicity assays indicate that matrine (LC₅₀: 3.54 mg·L^-1), spinetoram (LC₅₀: 4.12 mg·L^-1), and spinosad (LC₅₀: 9.68 mg·L^-1) exhibited potent contact toxicity against the 2^nd instar larvae. In the stomach toxicity tests, spinosad (LC₅₀: 0.01 mg·L^-1), matrin (LC₅₀: 0.10 mg·L^-1), spinetoram (LC₅₀: 0.31 mg·L^-1), methoxyfenozide (LC₅₀: 11.06 mg·L^-1), chlorfenapyr (LC₅₀: 38.80 mg·L^-1), and indoxacarb (LC₅₀: 49.87 mg·L^-1) exerted relatively optimal stomach toxic effects on the 2^nd instar larvae. The subsequent field efficacy trials reveal that spinetoram, chlorfenapyr, spinosad, and indoxacarb all showed remarkable control effects on E. grisescens larvae. Spinetoram achieved a control efficacy over 90% after 1 and 3 days of application, highlighting its rapid and remarkable properties. For the other three pesticides, their control efficacy surpassed 80% on the 7^th day, indicating ideal long-term effectiveness. The toxicity assessment of natural enemies indicates that the LC₅₀ values of spinetoram (LC₅₀: 5.39 mg·L^-1), and spinosad (LC₅₀: 39.75 mg·L^-1) for Arma chinensis were higher than those for the 2^nd instar larvae. This finding suggests that using spinetoram and spinosad to control E. grisescens in the field poses relatively low risks to natural enemies. Finally, the results of pesticide residue analysis shows that only indoxacarb remained at 0.30 mg·kg^-1 after 7 days of application, and no other pesticide treatments were detected, all of which met the maximum residue limit standards in China (GB 2763—2021). In conclusion, spinetoram and spinosad, characterized by their high efficiency and safety, were appropriate for rotational use to control the Ectropis grisescens.

Sorting fresh tea leaves can achieve high value tea production, but fresh tea leaves are prone to agglomeration and difficult to disperse, which affects the sorting results and efficiency. In this paper, disperse aggregates in fresh tea leaves by cross airflow. The fresh tea leaf agglomeration dispersing device based on cross airflow consists of a frame, opposite-facing photoelectric sensor, conveyer belt, slide rail, observation plate, movable hinge, air nozzle and other components. Based on CFD-DEM joint simulation, the influence of the air nozzle offset, air nozzle line spacing, and tilt angle of air nozzle on the dispersion degree was analyzed. Design-Expert 13 software was used to design a three-factor, three-level orthogonal test protocol, and the optimal parameter combination was obtained using response surface optimization. The experimental results show that when the air nozzle was arranged with the optimal combination of parameters, the rectangular area of dispersed fresh tea leaves obtained after dispersion was 0.343 m², and the percentage of fresh tea leaves area was 0.241, which were 90.6% and 50.6% higher than the tea fresh leaf material without dispersion, respectively. The relative errors between the experimental and predicted values was less than 5%. This device achieved effective dispersion of fresh tea leaf agglomerates, providing ideal material pretreatment conditions for subsequent accurate sorting.

Longjing tea appearance features are crucial for assessing tea quality. In order to intelligently evaluate the appearance characteristics of Longjing tea and quickly recognize the grades, a method combining image features and intelligent algorithms for appearance quality assessment was proposed. Images of the six grades of the standard Dafo Longjing tea were collected and their shape, color, and texture features were quantified and extracted to construct a database of tea appearance grade characteristics. The appearance features were fused and input into five machine learning models, namely, Decision Tree, Random Forest, K-Nearest Neighbor, Gaussian Bayesian, and Support Vector Machine, for grade recognition training. Three convolutional neural networks, VGG16, ResNet18 and DenseNet121 were compared to build a deep learning model for Longjing tea appearance evaluation. Then the model was optimized by optimizers and learning rate decay. The results show that the fusion of shape and texture data combined with Support Vector Machine was the optimal model for grade recognition, with an accuracy of 91.14% and an F₁ score of 91.20%. The ResNet18 network structure was chosen to establish the optimal model for appearance evaluation. After optimization by Adadelta optimizer and CosineAnnealingLR learning rate decay, the recognition accuracies of Longjing tea’s flatness, straightness, tenderness, and color all improved, reaching 99.21%, 99.51%, 99.56%, and 99.68%, respectively. This study provided a theoretical foundation for the digital evaluation of the appearance quality of tea.

Alkaloids, as a class of nitrogen-containing secondary metabolites characterized by remarkable chemical diversity, are widely distributed in higher plants, fungi, and bacteria. Most natural alkaloids possess biological activities such as antioxidant, anti-inflammatory, and anti-tumor effects. This review comprehensively summarized the identified alkaloid groups in tea and briefly analyzed their biological activities, including: (1) purine alkaloids, which regulate neural excitability by antagonizing adenosine receptors and inhibiting phosphodiesterase to regulate metabolic functions, exhibit anti-inflammatory, and other biological activities. (2) flavor alkaloids have effects in preventing diabetes and inhibiting cancer cell angiogenesis. (3) the mechanisms by which prenylated indole alkaloids exert anti-inflammatory effects, inhibit cancer cell growth and exert neuro-protective effects. Finally, the future research directions focusing on the identification, appraisal, synthesis and functional evaluation systems of tea alkaloids were proposed.

Tea plants [Camellia sinensis (L.) O. Kuntze] is important leaf cash crops in China, and its growth and development are affected by plant hormones. As one of the six classical plant hormones, brassinosteroids (BRs) play crucial roles in regulating both developmental processes and stress adaptation in tea plants. Steroid 5α-reductase is a key enzyme in the brassinosteroid biosynthesis pathway. To characterize steroid 5α-reductase in Camellia sinensis, the CsDET2 gene was cloned from tea cultivar ‘Shuchazao'. Then, the physicochemical properties, secondary and tertiary structures, sequence characteristics, phylogenetic relationships, and subcellular localization of the encoded protein were analyzed, along with the cis-acting elements in gene promoter region. Furthermore, the expression profile of CsDET2 was examined across different organs under abiotic stress conditions and during a 12 h/12 h photoperiod cycle. The results reveal that the CsDET2 gene contains a 783 bp open reading frame encoding 260 amino acids. The CsDET2 protein has a molecular weight of 30 158.97 Da with a theoretical isoelectric point of 9.28, and is predominantly composed of α-helices and random coils, containing a characteristic steroid dehydrogenase domain. Comparative sequence alignment with DET2 proteins from 15 species shows 78.25% amino acid sequence identity. Phylogenetic analysis suggests that CsDET2 shares the closest evolutionary relationship with AfDET2 from Actinidiarufa. Subcellular localization experiments confirm that CsDET2 is localized in the cytoplasm. Analysis of cis-acting elements reveals that the promoter region of CsDET2 contains 4 types of photo-responsive elements, 4 types of stress-responsive elements, 3 types of hormone responsive elements, and 5 types of transcription factor binding sites. The fluorescence quantification results show that CsDET2 was expressed in all organs, and the expression level was the highest in the old leaves. In the 12L/12D photoperiod, the expression level of CsDET2 decreased first and then increased during the daytime, increased first and then decreased at night, and the expression level of CsDET2 at night was higher than that during the daytime. The expression of CsDET2 shows significant changes under high temperature and salt stress treatments, and was regulated by exogenous gibberellins. The results provided a theoretical basis and valuable insights for further exploring the function of tea plant steroid 5α-reductase.

Anthocyanins exhibit diverse health benefits in humans, including antioxidant and anticancer effects, making them a key target for functional crop breeding. Anthocyanin synthase (ANS), a pivotal enzyme in anthocyanin biosynthesis, has been demonstrated to regulate anthocyanin accumulation in various crops. However, functional studies on ANS genes in tea plants (Camellia sinensis) remain limited. In this study, we identified a specifically highly expressed CsANS1 gene in the purple leaves of tea cultivar ‘Zijuan' through comparative transcriptome analysis of four tea cultivars with distinct leaf colors. Gene expression analysis reveals that CsANS1 expression in ‘Zijuan' was significantly higher than in other cultivars and other ANS family members (CsANS2 and CsANS3) in tea plants. Tissue-specific expression analysis further demonstrats that CsANS1 exhibited the highest expression level in ‘Zijuan' leaves, showing an expression trend of first increasing and then decreasing with the development of buds and leaves. Phylogenetic analysis indicats that sequence similarity among ANS gene copies within species is higher than that among interspecies homologs, and all members of the tea ANS family possess the highly conserved Fe(Ⅱ)/2OG dioxygenase domain. Comparative gene sequencing and protein tertiary structure prediction analyses reveal two non-synonymous mutations in the coding region of CsANS1 in ‘Zijuan', with the amino acid variation at position 165 potentially affecting local protein conformation. Following VIGS-mediated silencing of CsANS1, the anthocyanin content in ‘Zijuan' shoots significantly decreased, accompanied by a lightening of leaf color. In conclusion, this study confirms that CsANS1 is a key gene regulating high-level anthocyanin accumulation in ‘Zijuan' buds and leaves, providing an important molecular target for breeding high-anthocyanin tea cultivars.

Colletotrichum camelliae is the dominant pathogen causing tea anthracnose. This disease causes significant defoliation, which has a major impact on the following year's yield and results in great economic losses. Therefore, the early and timely detection of C. camelliae in tea leaves is of great significance for effective control of anthracnose in production. In this study, based on a loop-mediated isothermal amplification (LAMP) assay, a specific gene encoding a late embryogenesis abundant (LEA) domain protein from C. camelliae was selected for the design of LAMP primers. Three pairs of specific LAMP primers, including two outer primers, two inner primers, and two loop primers, were designed and selected. Subsequently, a LAMP assay for C. camelliae was established through specificity and sensitivity tests, and by detecting C. camelliae in artificially inoculated and infected tea leaves. The optimal reaction condition was determined to be at 65 ℃ for 30 min. The results were verified by 2% agarose gel electrophoresis with SYBR Green Ⅰ added. Specificity tests reveal that, only DNA extracted from C. camelliae isolates exhibited a positive amplification reaction. In sensitivity tests, the assay could detect genomic DNA templates of C. camelliae at a minimum concentration of 100 ag·µL^-1. The LAMP assay accurately detected C. camelliae in artificially inoculated diseased leaves and anthracnose-affected leaves of 18 tea germplasms in the field. In summary, the LAMP assay for detecting C. camelliae established in this study has the advantages of rapid, simple and high sensitivity, enabling the specific detection of C. camelliae and the quick diagnosis of tea anthracnose.

To explore the differences in tea leaf quality and metabolic profiles of a new seed-leaf dual-pupose tea cultivar ‘Jincha 1' under different cultivation patterns, the study investigated the phenological stages, lengths, weight per hundred buds of single bud, one bud with one leaf, and one bud with two leaves shoots under single plant sparse planting pattern and strip dense planting pattern. Moreover, comprehensive analyses were conducted on quality components and metabolomic profiling of the samples of one bud with two leaves. The results show that the tea cultivar ‘Jincha 1' under single plant sparse planting pattern yielded longer and heavier single buds, one bud with one leaf, and one bud with two leaves shoots compared to the strip dense planting pattern. Additionally, there is a delayed maturity period single plant sparse planting. Furthermore, the contents of tea polyphenols, catechins and gallic acid in the new shoots of single plant sparse planting pattern were 3.96, 5.06, and 1.19 percentage points higher than those of strip dense planting pattern, respectively. Conversely, strip dense planting resulted in higher total amino acid (1.27 percentage points) and theanine (0.21 percentage points) contents. A total of 163 significantly differential metabolites were identified by comparative metabolomics analysis, which were largely enriched in amino acid and polyphenol biosynthetic pathways. Notably, the contents of abscisic acid (ABA), gibberellin (GA), and jasmonic acid (JA) were higher in the single plant sparse planting pattern than those in the strip dense planting pattern. While, the levels of indoleacetic acid (IAA), 6-chloroadenosine phosphate (6-KT), and indole-3-butyric acid (IBA) in the single plant sparse planting pattern were lower than those in the strip dense planting pattern. This study reveals the mechanism by which different cultivation modes affect the tea quality through the regulation of endogenous hormones and metabolic pathways, providing a practical model for efficient cultivation in industrial promotion.

The color values of 865 colored tea germplasm were obtained by comparing them with the PANTONE and RHS plant color cards, and describing them in language. Based on the principles of color science and the descriptors and data standard for tea germplasm, the basis and method for leaf color identification and classification were established according to the coloring regularity of tea leaves. On the basis of the definition of leaf color, a framework of tea leaf color composition consisting of type, series, sub-series and color level was established. The existing tea leaf colors were drawn into a tea leaf color system diagram (leaf color wheel), including 5 types, 9 color series, 6 sub-series (belonging to 3 color series) and 72 color levels. This paper provided a scientific basis for the leaf color differentiation and accurate identification of colored tea germplasms.

To elucidate the quality characteristics of Yihong black tea, a systematic analysis was conducted on the quality attributes of Yihong black tea with different levels of tenderness based on sensory evaluation, colorimetric analysis, and targeted metabolomics. The results demonstrate that sensory evaluation scores exhibited a positive correlation with leaf tenderness. The theaflavin content exhibited an initial increase followed by a decline with the decrease in leaf tenderness, and the content of theaflavins was positively correlated with the color parameter L^* value of the tea infusion. The soluble sugar content elevated with the decrease in leaf tenderness, whereas the contents of tea polyphenols and total free amino acids gradually declined. Furthermore, a total of 162 non-volatile metabolites were identified based on the UPLC-MS/MS. Among them, 24 characteristic metabolites were characterized as marker compounds for distinguishing Yihong black tea with different levels of tenderness, including 10 flavonoids [hyperoside, kaempferol-3-O-(6''-trans-P-coumaroyl-2''-glucosyl) rhamnoside, quercetin 3-rutinoside-7-glucoside, keracyanin, kaempferol 3-rutinosidea, astragaline, kaempferol 3-O-galactoside, quercetin 3-rutinoside-7-galactoside, quercetin 3-O-rhamnoside-7-O-glucoside, quercetin 3-rutinoside], 7 catechins [(+)-catechin, catechin gallate, epicatechin, (-)-epigallocatechin, (-)-gallocatechin gallate, epigallocatechin gallate, (-)-epicatechin gallate], 4 amino acids [L-phenylalanine, L-arginine, D-(+)-pipecolinic acid, L-(-)-pipecolinic acid], 3 alkaloids [caffeine, theobromine, adenosine]. These results clearly defined the typical quality attributes of Yihong black tea as “amber-hued liquor, and a honeyed fruity bouquet” and further elucidated the characteristic metabolites responsible for the quality differences in Yihong black tea with different levels of tenderness, providing a scientific basis for optimizing processing techniques and precisely modulating flavor profiles, and facilitating standardized processing and quality enhancement of Yihong black tea.

Qingzhuan tea is a regional iconic product of Hubei Province. This study used Hubei-specific, pile-fermented (unpressed) Qingzhuan tea as a sample to optimize the water and alkali extraction processes via response surface methodology. The study then compared the physicochemical properties of two tea polysaccharides (TPS) and clarified their emulsion stability and loading effect over 10 days of storage. The results show that the optimal conditions for water extraction were 60 ℃, 367 W of ultrasonic power, a solid-to-liquid ratio of 1:40 and an extraction rate of (5.019±0.130)%. The optimal conditions for alkali extraction from the water-extracted tea residue were 85 ℃, a solid-to-liquid ratio of 1:40, pH 9.0 and an extraction rate of (1.101±0.034)%. The molecular weight, free radical scavenging rate for antioxidant activity, monosaccharide content, particle size, zeta potential, emulsion stability and loading capacity of water extracted TPS were higher than those of alkali-extracted TPS. TPS emulsions show good stability during the storage period of 10 days, and has a broad application prospect as a load material.

To further clarify the effects of the main compounds in white tea on blood glucose levels, the network pharmacology was used to conduct a correlation analysis between 8 main compounds in white tea and diabetes, and a zebrafish biological model was adopted for verification. The network pharmacology analysis reveals that blood glucose was primarily regulated by gallic acid, catechin group, and caffeine in white tea through four targets: TNF, p53, SRC and CASP3. The verification results of the zebrafish model show that the maximum tolerance concentrations of zebrafish to the different samples were as follows: 100.00 µg·mL^-1 (white tea soup), 6.25 µg·mL^-1 (gallic acid, caffeine), 12.50 µg·mL^-1 (EGCG), 25.00 µg·mL^-1 (ECG, EGC, GCG), 50.00 µg·mL^-1 (EC), and 150.00 µg·mL^-1 (C). At this concentration, the blood glucose values decreased significantly in all groups compared with the model group: the positive drug (ACA) group by 53.7%, the white tea soup group by 16.2%, the gallic acid group by 33.6%, the EGCG group by 47.3%, the ECG group by 30.0%, the EGC group by 52.6%, the GCG group by 25.8%, the EC group by 21.5%, and the C group by 29.4%. Only the caffeine group showed a significant blood glucose-elevating effect (P<0.05), with an increase of 16.9%. The qPCR results show that, compared with the blank group, the expression levels of TNF, SRC and CASP3 in the model group were significantly increased, while the expression level of TP53 was significantly decreased (P<0.05). Compared with the model group, the expression levels of TNF, SRC and CASP3 in the gallic acid and catechin groups were significantly decreased (P<0.05), while the expression level of TP53 was significantly increased (P<0.05). The expression levels of TNF and SRC in the caffeine group were significantly increased (P<0.05), while there were no significant differences in TP53 and CASP3. The results show that gallic acid and catechin components in white tea both exhibited significant hypoglycemic effects, which were mainly achieved by regulating four targets: TNF, p53, SRC and CASP3. In contrast, caffeine was found to have a significant blood glucose-elevating effect, primarily through TNF and SRC.

To investigate the effects of geographical origin and cultivar on green tea quality, this study analyzed the liquor color, physicochemical components, and in vitro antioxidant activities of eight green teas from Longnan, Gansu and Jinhua, Zhejiang. Correlation and cluster analyses were employed for a comprehensive evaluation. The results show that compared to Longnan green teas, Jinhua green teas exhibited brighter green liquor color and a fresher, sweeter aftertaste. In contrast, Longnan green teas contained higher levels of tea polyphenols, flavonoids, caffeine, vitamin C (VC), catechins, and mineral elements, as well as superior in vitro antioxidant activities, including DPPH radical scavenging ability, ABTS radical scavenging ability, hydroxyl radical (·OH) scavenging ability, and total antioxidant ability (T-AOC). Among the tested cultivars, Longnan Camellia sinensis cv. ‘Yunfeng 5' and Jinhua Camellia sinensis cv. ‘Jiaming 1' had the best overall quality and antioxidant performance. The correlation results show that the color, physical and chemical components and antioxidant capacity of tea decoction were closely correlated. Among them, tea polyphenols, VC and epigallocatechin gallate (EGCG) were positively correlated with the antioxidant ability of the four kinds of tea decoction (P<0.01). Cluster analysis divided the samples into two distinct groups corresponding to their geographical origins, indicating that origin had a greater influence on tea quality than cultivar. This study provided a theoretical foundation for evaluating the effects of geographical origin and cultivar on the antioxidant properties of green tea.

Soil aggregate is an important indicator of soil structure and fertility. Soil compaction and nutrient deficiency in tea gardens in subtropical red soil areas seriously affect the stability of soil carbon pools. Evaluating the effects of biochar-based fertilizer application on the organic carbon structure characteristics and physical stability of soil aggregates in tea gardens can help to reduce soil barriers and improve productivity in intensive tea gardens. In this study, a 40-year old Xishan tea garden in Guiping, Guangxi, located along the Tropic of Cancer, was selected as the research object. Three treatments [biochar-based fertilizer (BF), chemical fertilizer (F), and no fertilizer (CK)] were used for a field positioning test for two consecutive years to explore the soil aggregate structure, organic carbon distribution and physical stability of the tea garden. The results show that: (1) the application of biochar-based fertilizer increased soil pH value and cation exchange capacity (C_EC), and tended to decrease soil bulk density (B_D). The soil pH value under the treatment of biochar-based fertilizer increased by 0.18 and 0.31 respectively compared with the no fertilizer and chemical fertilizer treatments. The soil bulk density under the biochar-based fertilizer treatment decreased by 4.52% compared with the chemical fertilizer treatment. The cation exchange capacity under the biochar-based fertilizer treatment increased by 12.12% and 15.09% respectively compared with the no fertilizer and chemical fertilizer treatments. (2) The application of biochar-based fertilizer improved the structural stability of soil aggregates and promoted the formation of large aggregates with soil water stability. The values of water stability large aggregates (R_W0.25), mean mass diameter (D_MW) and geometric mean diameter (D_GM) of aggregates >0.25 mm under the biochar-based fertilizer treatment were increased by 15.34%, 23.94% and 34.48% compared with the chemical fertilizer treatment. (3) The application of biochar-based fertilizer increased the organic carbon content of soil macroaggregates, which was conducive to the storage of organic carbon in soil macroaggregates. The organic carbon content of the aggregate with particle size >2.00 mm under the biochar-based fertilizer treatment was significantly higher than that under the chemical fertilizer and no fertilizer treatments, increasing by 45.23% and 17.28%, respectively. The contribution rate of organic carbon in biochar-based fertilizer was 77.48% and 13.11% higher than that of chemical fertilizer and no fertilizer, respectively. The contribution rate of active organic carbon in aggregates under biochar-based fertilizer treatment was 50.40% higher than that under chemical fertilizer treatment. (4) The application of biochar-based fertilizer improved the stability of organic carbon in microaggregates. For aggregates with a particle size of >0.053-0.25 mm and ≤0.053 mm, the organic carbon oxidation stability coefficient (K_OS) under biochar-based fertilizer treatment increased by 82.42% and 77.78%, respectively, compared with that under no fertilizer treatment. For aggregates with particle size of >0.25-2.00 mm, the organic carbon oxidation stability coefficient under biochar-based fertilizer treatment decreased by 40.79% and 49.58%, respectively, compared to the chemical fertilizer and no fertilizer treatments. Biochar-based fertilizer treatment had a tendency to reduce the stability of organic carbon in large soil aggregates. The application of biochar-based fertilizer is conducive to the optimized management and carbon pool stability of tea gardens.

Milled tea is the raw material for the production of matcha and it is the most important factor in ensuring the quality of matcha. Rapid and effective sorting of milled tea improves its quality. Due to the low efficiency and high labor intensity of the current sorting process in milled tea production, an online sorting system for milled tea was developed in this study. This system is composed of a material conveying system, an image acquisition system, an image recognition system, a positioning system and a sorting execution control system. The image acquisition system is used to collect the milled tea image and make the milled tea image data set. According to the real-time and lightweight requirements of milled tea recognition, the EfficientNet backbone network and SimSPPF module were introduced based on the YOLOv5s model, and the YOLOv5s-EfficientNet-SimSPPF model was improved and designed. On the basis of ensuring the recognition precision, the model recognition speed was improved and the model size was reduced. The established test set was used to evaluate the recognition performance of YOLOv5s, YOLOv5s-EfficientNet, YOLOv5s-SimSPPF and YOLOv5s-EfficientNet-SimSPPF on the PC. The recognition precision, recall, mAP@0.5, inference time and model size of YOLOv5s-EfficientNet-SimSPPF were 0.993, 0.981, 0.995, 6.3 ms and 2.85 MB, respectively. This study also proposed a sorting control algorithm for online sorting based on the online recognition results of milled tea. In addition, an auxiliary algorithm was proposed to prevent low-precision secondary recognition and secondary positioning of the milled tea on the boundary of the field of view of the industrial camera during the sorting process. The YOLOv5s-EfficientNet-SimSPPF model was deployed to the edge device Jetson Nano B01, and the model was tested using the test set. The recognition precision and speed were 0.982 ms and 37.5 ms, respectively. The results show that the real-time milled tea recognition can essentially be achieved by deploying the model migration to the developed online milled tea sorting system. Finally, the milled tea separation was carried out on the designed and developed platform, and the average separation accuracy rate of mixed milled tea leaves and milled tea stems reached 97.0%. The online milled tea sorting system proposed in this paper can meet the actual needs of online milled tea sorting, and can be used as an effective tool for the fine processing of matcha and milled tea sorting operation, providing a reference for online recognition and continuous sorting of other agricultural products.

To explore the effects of tea light complementary mode on the growth environment, yield performance and economic benefits, the microclimate environment such as temperature, humidity and light in the tea garden-PV complementary model was analyzed in this study with the open-air tea garden as a control. Indicators such as tea bud germination and growth, photosynthetic rate, and fresh leaf yield were detected, and the photovoltaic power generation was simulated and calculated. The overall economic benefits of the tea garden were analyzed. The results show that the photosynthetically active radiation of the tea canopy in photovoltaic tea gardens was lower than that in open-air tea gardens. The average minimum temperature of tea canopy in photovoltaic tea gardens at night in spring (March) was 0.63 ℃ higher than that in open-air tea gardens, and the average maximum temperature in daytime in summer (July) was 1.80 ℃lower than that in open-air tea gardens. The average relative humidity of tea canopy in photovoltaic tea gardens was higher than that in open-air tea gardens. The tea buds in photovoltaic tea gardens germinated and grew faster, and the utilization efficiency of light radiation was higher. The yield per unit area of the picking area in different harvesting seasons was 9.74%-28.84% higher than that of the open-air tea gardens. The overall output of the tea garden decreased by 23.11% to 34.16% due to the occupation of land for the construction of photovoltaic modules. The annual income of photovoltaic tea gardens, including power generation revenue, was 6.030×10⁵ CNY per hectare, while the annual income of open-air tea gardens was 2.249×10⁵ CNY. Considering the one-time investment cost of 3.740 3 million CNY for building photovoltaic modules, the total revenue of photovoltaic tea gardens will exceed that of open-air tea gardens after 9 years. This study has certain guiding and referential significance for the application and promotion of the tea-light complementary agricultural model in southern China.

During the processing of tea beverages, a considerable amount of foam is generated, which adversely affects the quality, stability, and appearance of the products and is a major challenge for the industry. Proper understanding and management of the causes of foam generation and control technologies are critical to optimizing the production process. This article systematically examined the fundamental theory of foam generation and analyzed the impact of various factors such as tea components, temperature and pH levels on this process. Additionally, it outlined different methods for foam elimination, discussed defoaming principles, and categorized commonly used anti-foaming agents in the food industry, intending to provide valuable references for optimizing tea beverage processing technology.

The Patellin (PATL) gene family is essential for plant growth, development and environmental adaptation. This study systematically identified and analyzed the CsPATL gene family in tea plants (Camellia sinensis). Five members of the CsPATL family were identified using a variety of bioinformatics techniques, and the physicochemical characteristics of their protein sequences were analyzed. The results show that the five CsPATL genes encode 232~585 amino acids, their molecular weights are 26.31~64.69 kDa, and their theoretical isoelectric points are 4.65~9.35. The chromosomal localization of these genes and the cis-elements in their promoter sequences were also analyzed in detail, and it was found that these genes were unevenly distributed on four chromosomes, and were mainly involved in phytohormone response, abiotic stress response, and light response, with light-responsive elements occupying a significant proportion in particular. Y1H, EMSA, and dual-luciferase assays confirm that Cshdz7 can directly bind to the CsPATL1 promoter and promote CsPATL1 gene expression. These findings provided a new perspective on the role of the CsPATL family genes in plant developmental regulation of tea plant development.

Codon usage bias serves as an important driving force for gene expression regulation and molecular evolution, and is of particular importance in the study of plant organellar genomes. Camellia sinensis cv. ‘Zhuyeqi’, an important tea cultivar in China, has not yet received a systematic report on the codon usage patterns of its organellar genomes. This study was systematic bioinformatic analysis of the 52 chloroplast-encoded genes and 29 mitochondrial-encoded genes of ‘Zhuyeqi’. The results reveal that: (1) both the chloroplast genome (ENC=44.64±3.25) and the mitochondrial genome (ENC=51.98±3.47) exhibit weak codon usage bias, with the chloroplast bias primarily driven by natural selection (GC3s and ENC correlation R²=0.482). While the mitochondrial bias is jointly influenced by natural selection and mutational pressure (R²=0.312). (2) Relative synonymous codon usage (RSCU) analysis demonstrates that both organellar genomes significantly prefer synonymous codons ending in A/U, and the highly expressed chloroplast genes (rpoC2, psbA) exhibit stronger codon preferences. (3) a multi-parameter screening approach identified 20 optimal chloroplast codons (GCA, GCU) and 23 optimal mitochondrial codons (GCC, AGG). This study provided elucidation of the codon usage characteristics and evolutionary driving forces in the organellar genomes of Camellia sinensis cv. ‘Zhuyeqi’, offering crucial theoretical guidance for the optimization of the tea molecular breeding system and the efficient expression of exogenous genes.

To clarify the genetic diversity of tea germplasm resources in Hunan Province, explore the genetic structure of germplasm resources for accurate identification and evaluation, genotyping by targeted sequencing (GBTS) was used to genotype and analyze the genetic diversity of 76 252 SNP loci in 78 tea germplasm resources in Hunan Province. A total of 30 agronomic traits and 15 biochemical components of this batch of resources were accurately identified. The results show that there was abundant genetic variation among 78 tea germplasm resources in Hunan Province, with a genetic diversity index of 0.07-2.08 for phenotypic traits and a coefficient of variation of 2.26%-47.50%. The smallest was the number of calyxs and the largest was the depth of leaf serration. The genetic diversity index of the biochemical components was 1.36-2.09, and the coefficient of variation was 5.90%-118.49%, with the smallest being water extract and the largest being gallic acid. When the Euclidean distance was 20, the 78 tea germplasm resources could be divided into five groups, and there were significant differences in leaf length, leaf size, leaf base shape, ratio of polyphenols/amino acids, GA, THEO, GC, EGC, EC, EGCG, GCG and ECG in groups Ⅰ and Ⅲ. Based on the genotype detection results of 78 resources, a phylogenetic tree was constructed, and 78 resources could be divided into three groups. At the same time, this study identified 23 tea resources with specific phenotypic traits, high levels of functional components such as amino acids, theobromine and caffeine. The results of this study could provide a basis for the protection and utilization of tea germplasm resources in Hunan.

This study investigated how the conversion of forests to tea plantations and associated management practices affect the dynamics of carbon (C) and nitrogen (N) fractions across soil profiles in tea agroecosystems, with a focus on fungal community-mediated regulatory mechanisms. We compared forest soils with tea plantation soils under low-, medium-, and high-intensity fertilization regimes. Soil cores were systematically collected from four depth intervals (0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm) to analyze vertical stratification of C/N fractions, nutrient stoichiometry, and fungal community composition. The results reveal that tea plantations management significantly enhanced soil organic carbon and total nitrogen contents in the 0-10 cm soil layer compared to forest soil. Under high-input conditions, total carbon and nitrogen reached 46.57 g·kg^-1 and 5.13 g·kg^-1, respectively, increasing by 68.12% and 88.60% compared to low-input tea plantations. Land-use conversion and fertilization intensity gradients in tea plantations significantly modified fungal community structure and composition, with these changes being mainly driven by soil nutrient availability, including available phosphorus (AP), available potassium (AK), and total nitrogen (TN). In addition, fungal richness demonstrates a progressive decline across soil depth gradients (0-60 cm). Further analyses reveals that Dothideomycetes and Umbelopsidiomycetes exhibited significant positive correlations with soil C and N fractions, whereas Mortierellomycetes, Geminibasidiomycetes and Mucoromycotina_cls_Incertae_sedis showed pronounced negative correlations. Variations in the relative abundance of these taxa may strongly influence carbon and nitrogen cycling in tea plantation soils. Therefore, the conversion of forests to tea plantations and different fertilization management practices regulate soil carbon and nitrogen accumulation by influencing the structure of soil fungal communities and the abundance of dominant taxa.

L-type lectin receptor-like kinases (LecRKs) constitute a significant subfamily of plant receptor-like kinases, playing pivotal roles in plant development and immune responses. In this study, the CsLecRK gene family was systematically identified and analyzed in Camellia sinensis to explore their functions in growth, development and disease resistance. A total of 59 L-type CsLecRKs containing PF00069 and PF00139 domains were identified through HMMsearch analysis. Phylogenetic analysis shows these genes could be classified into 5 subgroups, revealing notable differences in exon-intron structures among the subgroups. Promoter region analysis shows enrichment of cis-acting elements associated with hormone responses and stress signaling pathways. Transcriptome data reveals that L-type CsLecRKs exhibited differential expressions in different tea plant tissues. qRT-PCR validation demonstrates that CsLecRK IV.1.2 and CsLecRK S.5 were significantly upregulated during the early stage of Colletotrichum camelliae infection and the later stages of Pestalotiopsis spp. infection. Notably, their expression levels were substantially higher in the resistant cultivar ‘Qianmei 419’ compared to the susceptible cultivar ‘Qianmei 818’, indicating their critical involvement in the immune response to pathogen infection. This study highlighted the critical mechanisms of L-type CsLecRKs in tea plant defenses against brown blight and anthracnose, elucidated the expression profiles of CsLecRK IV.1.2 and CsLecRK S.5 during pathogen infection, and demonstrated their potential to enhance disease resistance by activating the tea plant immune system. These findings provided valuable genetic resources and theoretical support for molecular breeding as well as green disease control strategies in tea plants.

Tea plant [Camellia sinensis (L.) O. Kuntze] is an important agricultural economic crop in China. Tea leaf spot disease is one of the most important leaf diseases of tea plants. It seriously affects the yield and quality of tea. In 2023, a tea leaf spot disease was found in a tea garden in Menghai County, Xishuangbanna Dai Autonomous Prefecture Yunnan Province. In order to clarify the pathogen, the tissue isolation method and wound inoculation method were used to isolate and determine the pathogenicity of the pathogen. The morphological characteristics were observed and combined with molecular biology techniques to determine the type of pathogen. The results show that the three strains could infect tea leaves and were the causal agents of tea leaf spot. The pathogen causing tea leaf spot was identified as Nigrospora musae by observing its morphological characteristics and phylogenetic analysis of multiple genes (ITS, TUB2 and TEF-1α). The results of this study provided a theoretical basis for the prevention and control of tea leaf spot caused by the pathogen.

In response to the problems of inadequate agricultural equipment and poor slope performance in tea gardens of hilly areas, a tracked ploughing machine suitable for hilly tea plantations was designed and developed, with a focus on slope performance. The main structural parameters of the chassis were designed, and the dynamic simulation was used to analyze the machine's ability to traverse across and along slopes. The simulation results show that the maximum slope for the machine to traverse across was 22°, and the maximum slope for the machine to traverse along was 31°. To explore the quality of excavator tillage, based on the theoretical analysis of the tillage movement trajectory, the tillage advance speed was optimized by dynamics, and the optimal tillage advance speed of 400-450 mm·s^-1 was obtained for excavators. To further verify the rationality of the parameters and the reliability of the simulation results, field tests were conducted on uphill slopes. The results show that the maximum climbing ability of the machine on uphill slopes was 32°, with an error of 3.22% compared to the theoretical climbing angle. The results validate the accuracy and reliability of the theoretical calculations and simulations, demonstrating that the designed ploughing machine has good maneuverability and can fully meet the uphill climbing needs of hilly areas, providing an effective solution to the problem of tea plantation cultivation.

To solve the problems of high resistance and poor operation efficiency caused by soil compaction and stickiness in tea plantation cultivation, this study designed a tea plantation composite biomimetic tillage shovel based on the mole claw toe as a biomimetic prototype, and integrated it with a four-bar mechanism to develop a tea garden tillage machine. Firstly, a simulation analysis of the tillage process of a tea garden bionic tillage shovel was carried out based on the coupling algorithm of Discrete Element Method (DEM) and Multi Body Dynamics (MBD). At the same time, Design Expert 13 experimental design software was used to design and carry out a three-factor three-level simulation orthogonal combination experiment. It was found that when the tillage depth was 100 mm, the optimal working parameters of the tea garden biomimetic tillage machine with a composite biomimetic tillage shovel were the plowing shovel insertion angle of 33.506°, the driving arm speed of 289.923 r·min^-1, and the tillage machine forward speed of 0.2 m·s^-1. Subsequently, a comparative analysis of soil disturbance simulation based on soil particle velocity distribution was conducted under these working parameters. Finally, a comparative experiment was conducted in tea gardens using a composite biomimetic tillage shovel and a prototype shovel under the same working parameters. The results show that compared with the prototype shovel, the average resistance of the tea garden biomimetic tillage machine equipped with a composite biomimetic shovel was reduced by 5.70%, and the performance evaluation indicators such as soil fragmentation rate were improved. Its working performance can meet the requirements of tea garden cultivation.

Changes in amino acids and polyphenols in leaves and stems during withering are critical for the formation of the material basis of tea flavor. This study systematically analyzed the differential accumulation patterns of amino acids and polyphenols in tea leaves and stems , as well as their changes during withering. The results show that the phenol-ammonia ratio in the leaves (4.66-6.36) was higher than that in the stems (1.97-2.59) during withering. The free amino acid content in tender stems (7.44%) was significantly higher than that in fresh leaves (2.22%). A total of 44 amino acids and their derivatives show differential accumulation between the two tissues, of which three (theanine, aminobutyric acid, and pipecolic acid) were found to be highly accumulated in the stems. No significant difference in total tea polyphenol content was observed between fresh leaves and tender stems. However, 97 polyphenolic compounds show differential accumulation between the two tissues. Gallate-type catechins and most flavonols and flavonol glycosides were more highly accumulated in the leaves, whereas non-gallate-type catechins were more abundant in the stems. During the withering process, the total content of free amino acids increased in the leaves but it continued to decrease in the stems. A total of 21 and 15 amino acids and derivatives underwent significant changes during the withering process in leaves and stems, respectively. The changing trends of tea polyphenol content in leaves and stems were relatively consistent, with 49 and 35 polyphenolic compounds showing significant changes during withering, respectively. The results of this study indicate that the leaf-stem ratio in tea raw materials plays a critical role in the formation of tea quality during subsequent processing, providing a theoretical basis for the development of withering regulation technologies based on leaf-to-stem ratio considerations.