Journal of Tea Science

Nitrogen Metabolism Genes in Tea Plant: Research Progress on the Environmental Stress Adaptation Mechanism and Breeding Application

ZHOU Yide, CHEN Jialin, WU Junmei, ZHAO Hongbo, SUN Binmei, LIU Shaoqun, ZHENG Peng

Journal of Tea Science. 2025, 45(4): 545-558. doi:10.13305/j.cnki.jts.2025.04.010

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Nitrogen metabolism genes play a key role in tea plants′ response to various environmental stresses. They do this mainly by regulating metabolites in different pathways. In recent years, significant progress has been made in the study of nitrogen metabolism genes in tea plants using techniques such as transcriptome and metabolome analysis, genome identification. However, there are still many scientific problems that need to be solved urgently, such as the low genetic transformation efficiency of tea plants, the limited research on gene epigenetics, and the limited application of gene breeding in production. This article systematically summarized the expression patterns of nitrogen metabolism genes in tea plants under different stress conditions, organs, and soil elements, as well as the research progress on the regulation mechanism of carbon and nitrogen balance in tea plants under different stresses, revealing the importance of these genes in tea plant stress adaptation and quality improvement. In addition, the research methods, transgenic technology, and breeding applications of nitrogen metabolism genes in tea plants were discussed in order to provide reference for the study of nitrogen metabolism gene regulation mechanisms and breeding research in tea plants.

Identification of Circadian Clock CsLUX Gene and Its Effects on Photosynthetic Characteristics in Tea Plants

SUN Mengzhen, HU Zhihang, YANG Kaixin, ZHANG Jiaqi, ZHANG Nan, XIONG Aisheng, LIU Hui, ZHUANG Jing

Journal of Tea Science. 2025, 45(4): 559-570. doi:10.13305/j.cnki.jts.2025.04.004

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Tea is a cash crop with large cultivated area in China, and its growth and development mechanism are strictly regulated by genes related to biological clock. In this study, the CsLUX gene was cloned using cDNA from tea cultivar ‘Longjing 43’ as template and sequence alignment and phylogenetic analysis were performed. Within two photoperiodic periods (48 h), the relative expression of CsLUX gene was detected by RT-qPCR, and photosynthetic parameters, stomatal opening and chlorophyll contents in tea leaves were also determined. The total length of CsLUX gene is 951 bp, encoding a hydrophilic protein composed of 316 amino acids. The secondary structure is mainly composed of α-helix and random curling. CsLUX is closely related to CCA1, ELF3 and other key components of the biological clock. The variation trend of photosynthetic parameters in tea leaves at different time points was basically consistent with stomatal opening, and the value of chlorophyll SPAD was basically stable. The relative expression of CsLUX reached its peak under dark conditions and maintained a low expression level during the day in response to changes in circadian rhythm. The expression of CsLUX gene was correlated with the rhythmic changes of photosynthetic parameters in two photoperiodic periods (48 h) in tea plants.

Analysis of Leaf Structure and Biochemical Quality Components of ‘Mayu’ Tea Germplasm Resources

YAN Huiting, WANG Yanyan, LU Jianwei, RAO Zilei, LI Yuanyuan, CHANG Runrun, ZHAO Hongyan, YANG Juncong, ZHANG Lilan, BAI Bapu, LU Liping, BAI Bing, WANG Baijuan, GAO Jun, LIU Zhiwei

Journal of Tea Science. 2025, 45(4): 571-586. doi:10.13305/j.cnki.jts.2025.04.006

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Camellia sinensis var. pubilimba ‘Mayu’ is a dominant tea cultivar in Lüchun County, Yunnan. This study systematically analyzed the leaf anatomical structures and biochemical components of 28 germplasms using C. sinensis var. sinensis (CSS) and C. sinensis var. assamica (CSA) as controls. This study established a comprehensive evaluation system for germplasm resources for the first time. Key findings include: (1) M4 and M5 in the ‘Mayu’ tea group (MY) exhibits higher stomatal density than the controls, with a 30.0% and 10.6% reduction in stomatal area relative to CSS and CSA, respectively. The MY group exhibits unique undulated wax layers in the upper epidermis. (2) Cold resistance evaluation via membership function analysis identifies M4 and M5 germplasms with the highest scores (0.975 and 0.689), while the palisade-to-spongy tissue ratio shows a significant positive influence on the cold resistance (β=0.179, P<0.01). (3) Biochemical profiling reveals high stability in ‘Mayu’ tea’s water extracts (46.8%) and tea polyphenols (32.14%) (coefficient of variation, CV<5%). Its phenolic-to-amino acid ratio (9.05-14.54) indicates suitability for both black and green tea processing. The catechin quality index of ‘Mayu’ tea significantly surpassed controls (P<0.05), with bitter amino acids reduced by 18.04% compared to CSS and umami amino acids increased by 17.76% relative to CSA. While sweet amino acids show no significant inter-varietal differences. (4) Ten characteristic markers (including methionine, theanine, caffeine, and seven catechin derivatives) were identified through principal component analysis combined with differential metabolite screening, enabling discrimination of ‘Mayu’ tea from controls. This study elucidated the germplasm specificity of ‘Mayu’ tea from structural adaptation and biochemical perspectives, providing a theoretical foundation for its conservation, breeding, and functional component development.

Analysis of Codon Usage Bias in Chloroplast and Mitochondrial Genomes of Camellia sinensis cv. ‘Baihaozao’

ZENG Wenjuan, LIU Shan, WEN Cong, ZHANG Qixiang, HUANG Jing, GONG Yihui, CHEN Zhiyin

Journal of Tea Science. 2025, 45(4): 587-603. doi:10.13305/j.cnki.jts.2025.04.005

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Codon usage bias serves as a critical driving mechanism in gene expression regulation and molecular evolution, holding significant biological importance in the evolution of organelle genomes in plants. This study focused on the economically important tea cultivar ‘Baihaozao’ (Camellia sinensis cv. ‘Baihaozao’) and systematically analyzed the codon usage patterns and evolutionary drivers of its chloroplast (52 genes) and mitochondrial (29 genes) genomes for the first time. The results indicate: (1) the average effective codon number (ENC=44.57±4.59) of the chloroplast genome is significantly lower than that of the mitochondrial genome (ENC=51.87±5.31), with both exhibiting weak preference characteristics. Neutrality analysis reveals that the chloroplast's preference is primarily driven by natural selection (correlation between GC_3s and ENC, R² =-0.016), whereas the mitochondrial genome is regulated by a combination of natural selection and mutational pressure (R² = -0.11), which is consistent with the evolutionary constraints observed in the organelle genomes of dicotyledons. (2) RSCU analysis shows that both types of organelle genomes significantly prefer synonymous codons ending in A/U, with high-expression chloroplast genes (e.g., ndhA, rps14) exhibiting a stronger preference for A/U terminal codons. This suggests that translational selection optimizes highly expressed genes. (3) Through multivariate statistical screening, 18 optimal codons were identified for the chloroplast genome (e.g., GCA, GCU) and 18 optimal codons for the mitochondrial genome (e.g., GCA, AGA). GCA was favored in both organelle types, reflecting the adaptive convergence of functional genes across organelles. This study elucidated the heterogeneity of codon usage characteristics in the organelle genomes of ‘Baihaozao’ and their evolutionary drivers for the first time, providing a theoretical basis for the adaptive optimization of exogenous genes and the construction of cross-organelle expression regulatory networks in molecular tea breeding.

Study on Distribution of α-Dicarbonyl in Different Teas

CHEN Wenxue, ZHU Li, LIU Yueyun, JIANG Yongwen, ZHU Hongkai

Journal of Tea Science. 2025, 45(4): 604-614. doi:10.13305/j.cnki.jts.20250312.001

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Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to analyze the contents and composition of 10 α-dicarbonyl compounds in tea by detecting stable quinoxaline derivatives formed by reactions between α-dicarbonyl compounds and o-phenylenediamine. The results demonstrate that 3-deoxyglucosone was the predominant dicarbonyl compound in all six major tea categories. The high-temperature de-enzyming process was identified as the primary driver for the formation of short-chain α-dicarbonyl compounds in green tea, yellow tea and oolong tea. While relatively lower drying temperatures significantly influenced the formation of long-chain α-dicarbonyl compounds in white tea and dark tea. The total contents of α-dicarbonyl compounds in green tea, yellow tea, black tea and oolong tea exhibited an increasing trend with the oxidation degree of catechins. Additionally, the absence of rolling during white tea processing and microbial activity during the pile-fermentation process of dark tea were critical factors for the accumulation of α-dicarbonyl compounds.

Investigation on the Helopeltis (Hemiptera) Species in Tea Gardens of China

MENG Zhaona, Fida Hussain Magsi, ZHAO Dongxiang, ZHOU You, LI Jianlong, NONG Hongqiu, LONG Yaqin, ZHAO Yuanyan, HUANG Liyun, BIAN Lei, LI Zhaoqun, LUO Zongxiu, XIU Chunli, FU Nanxia, CHEN Zongmao, CAI Xiaoming

Journal of Tea Science. 2025, 45(4): 615-624. doi:10.13305/j.cnki.jts.2025.04.003

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To clarify the occurrence species of Helopeltis, which is an important tropical economic pest in tea gardens of China, a total of 1 710 samples of Helopeltis adults were collected from 14 tea gardens in Hainan, Guangdong, Guangxi and Yunnan provinces. The collected bugs were reared in laboratory, and the morphology of eggs, nymphs and adults were observed. Three species were identified, including H. theivora Waterhouse, H. cinchonae Mann, and H. fasciaticollis Poppius. H. cinchonae was first found in tea gardens of China, H. cinchonae and H. theivora were the main species of Helopeltis in tea gardens of China. Damage characteristics of the three species on tea plants were similar. The three species could be distinguished based on the color of body and the antennae of males. The research shows that there were at least 3 species of Helopeltis in tea gardens of China.

Determination of 20 Phthalate Acid Esters in Tea Leaves by GC-MS/MS

SUN Yu, ZHOU Li, ZHANG Xinfu, SUN Hezhi

Journal of Tea Science. 2025, 45(4): 625-636. doi:10.13305/j.cnki.jts.2025.04.007

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In this paper, an analytical method for the simultaneous determination of 20 phthalate esters in tea fresh leaves was developed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The phthalate esters in tea fresh leaves were extracted by 0.1% acetonitrile acetate, salted out with sodium chloride, cleaned up with a florisil solid phase extraction column, resolved with acetonitrile, separated by temperature programmed chromatography, monitored with multiple reaction monitoring (MRM) mode, and quantified by the external standard method. Through the optimization of sample extraction, purification and chromatographic conditions, good linearity of the target compounds was obtained in the concentration range of 0.010-2.0 mg·kg^-1 with the corresponding coefficient of determination R²>0.995 5. The average recoveries ranged from 70% to 118% at the three spiked levels of 0.010 mg·kg^-1, 0.10 mg·kg^-1 and 1.0 mg·kg^-1, with the relative standard deviations (RSDs) of <17.8%. The limits of quantification were 0.010~0.050 mg·kg^-1. The method is stable and reliable, and it can meet the needs of the determination of phthalate acid esters in tea fresh leaves.

Analysis of Volatile Flavor Compounds and Microbial Diversity in Anhua Black Tea Processed by Different Fermentation Techniques

HOU Aixiang, YANG Xiaolu, WU Wenliang, XIAO Yu, LI Shi, HUANG Yiwen, JU Rongfang

Journal of Tea Science. 2025, 45(4): 637-654. doi:10.13305/j.cnki.jts.2025.04.009

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This study investigated the characteristic aroma components and microbial diversity during long term and short term fermentation processes of Anhua black tea. The research employed headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), as well as 16 S rRNA and ITS high-throughput sequencing technologies. The results show that 82 volatile components were detected in Anhua black tea with distinct fermentation processes, mainly include alcohols, esters, and aldehydes, collectively accounting for approximately 85% of the total volatile content. The overall volatile components initially increased and subsequently decreased during processing. Based on thresholds of odor activity value (OAV)>1 and variable importance in projection (VIP)>1, 14 key differential volatile components were identified in the black tea of short and long term fermentation processes, including citral, linalool, phenethyl alcohol, phenylacetaldehyde, methyl salicylate, β-myrcene, β-ionone, et al. The dominant bacteria of Anhua black tea include Sphingomonas, Methylobacterium, Aureimonas, and the dominant fungi include Cladosporium, Alternaria and Setophoma. The genera Aureimonas, Enterobacter, Aspergillus, and Pseudopithomyces were significantly correlated with distinct fermentation processes. This study provided a theoretical reference and basis for the scientific processing and flavor analysis of Anhua black tea.

Digital Evaluation of Black Tea Hairs Quality Based on Region of Interest Image Segmentation

TONG Chen, LIANG Xiuhua, WANG Zhouli, FAN Dongmei, LIN Zhaoshui, WU Xiaomei, QUE Yangzhan, JIN Minli, LIN Jie

Journal of Tea Science. 2025, 45(4): 655-670. doi:10.13305/j.cnki.jts.2025.04.008

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Tea hairs are an important indicator for evaluating the appearance quality of black tea. Currently, the evaluation mainly relies on the sensory assessment of professionals, which is highly subjective and abstract, lacking objective and digital quality evaluation methods. To construct a digital evaluation method for the quality of tea hairs, this study collected images of Qimen black tea samples with three different tea hairs quality grades. The HSV color image segmentation technique was used to extract the HSV color space component features of the region of interest (ROI), and a segmentation index (SI) was constructed to retrieve the optimal segmentation thresholds for tea hairs, tea body, and shadows. The image segmentation effect was qualitatively and quantitatively evaluated using the masking method and pixel point discrimination, and a quantification method for the proportion of tea hairs was established. The results show that the average segmentation accuracy of tea hairs, tea body, and shadow areas reached 98.70%. Furthermore, through the quantification of the proportion of tea hairs, the recommended hairs proportion thresholds for the three tea hairs quality grades of Qimen black tea (“Prominent golden hairs”, “Observable hairs”, and “Less hairs”) were obtained. The linear regression analysis of different hairs gradient blended tea samples (R²=0.958, P<0.01) and the generalization application effects on ‘Dianhong’ and ‘Jinjunmei’ indicate that the digital evaluation method of tea hairs quality constructed in this study has good adaptability in different hairs quantity intervals and different black tea categories.

Collaborative Picking Planning for A Dual-Arm Tea-Picking Robot

JIA Jiangming, WANG Xiang, ZHOU Yujie, WU Chuanyu, CHEN Jianneng, YU Rong, LI Yujie

Journal of Tea Science. 2025, 45(4): 671-686. doi:10.13305/j.cnki.jts.20250617.001

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In recent years, multi-arm tea-picking robots have become a research hotspot due to the shortage of labor, rising labor costs, and the demand for high-precision picking in the high-quality tea industry. A collaborative planning method that dynamically allocates the space for picking points was proposed, and the path planning of the robotic arm was optimized by combining the ant colony algorithm and the picking point priority in order to improve the operational efficiency of the tea-picking robot. Simulation results show that the average time for one-shoot picking was 1.41 s, and the time ratio for dual-arm synchronous operation was 91.95%. Compared to the 62.86% coverage rate of the two-space segmentation method, this method achieved full coverage of the space. To overcome the limitations of the existing independent operation mode of the depth camera, a dynamic addition of picking point planning was further proposed, which realized the synchronous operation of the depth camera and the robotic arm. Field experiment results show that the tea-picking robot adopts the picking point allocation method that dynamically divides the operating space and the double-arm collaborative planning method that dynamically divides the space for picking point allocation. The average time for one-shoot picking was 1.52 s, a 29.95% improvement compared to the one-arm tea-picking robot. This method not only significantly improves the operational efficiency of the tea-picking robot but also achieves full coverage of the space, ensuring efficient collaborative picking.

The Impact of Water Treatment Technology on the Characteristic Aroma of Xinyang Maojian During Processing

ZHENG Jie, HOU Ziyan, YI Chao, HUANG Shouyan, GUO Junqi, SU Hui, ZHOU Qiongqiong, ZHAN Qiangguo, ZHAO Renliang

Journal of Tea Science. 2025, 45(4): 687-698. doi:10.13305/j.cnki.jts.2025.04.001

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To investigate the dynamic changes of the characteristic aroma of Xinyang Maojian during processing and the impact of water treatment processes on its aroma, this study took Xinyang Maojian tea made from the tea cultivar ‘Xinyang 10’ as the research object. The aroma components and their relative contents in samples of different stages, including fresh leaves, fixation, rehumidification, rolling, shaping, and drying, using both water treatment and traditional methods, were identified and analyzed using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) technology. The results show that a total of 81 volatile metabolites were identified in the experimental samples, among which high contents of esters, terpenes, and heterocyclic compounds were found in Xinyang Maojian and they were considered as the main aroma-contributing substances. After fresh leaves were treated with water, the contents of volatile components decreased rapidly, and then tended to be stable in each processing stage. Compared with the traditional process, there were 7 volatile components with significant differences in the aroma components of the finished tea processed by water treatment, among which 4 volatile components had higher relative odor activity value (ROAV) in the water treatment samples than in the traditional process. This study deeply analyzed the dynamic changes of aroma components during the Xinyang Maojian processing and the impact of water treatment technology on its aroma. This paper provided a scientific basis for the quality improvement of Xinyang Maojian and the application of water treatment technology.

Differences in Digestive Stability of Catechins in Dry Tea and Instant Tea Powder

ZHANG Mengxue, JIANG Heyuan, WANG Weiwei, YE Shuixin

Journal of Tea Science. 2025, 45(4): 699-711. doi:10.13305/j.cnki.jts.20250619.001

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The effects of different pH and digestive enzymes in tea soup on tea polyphenols (TP), catechins (CATE) and their antioxidant activities were investigated by using an in vitro simulated digestion model, and the differences between dry tea and instant tea powder were compared. The TP concentration was determined by Folin phenol method, and the catechins were quantitatively analyzed by high performance liquid chromatography (HPLC). The antioxidant activities of the two kinds of tea soups were comprehensively evaluated by Ferric reducing ability of plasma (FRAP), 1,1-diphenyl-2-trinitrophenylhydrazine free radical (DPPH) and 2,2ʹ- diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid free radical (ABTS). The results show that the TP concentration (874.19 mg·L^-1) of black instant tea powder before simulated digestion was 1.59 times that of dry tea soup (551.50 mg·L^-1), the cate concentration (239.58 mg·L^-1) was 1.68 times that of dry tea soup (142.98 mg·L^-1), and the antioxidant activity was about twice that of dry tea soup. After gastrointestinal simulated digestion, the stability of tea soup cate and antioxidant activity of black instant tea powder were lower than that of dry tea, which may be related to the high proportion of epigallocatechin gallate (EGCG)+epigallocatechin (EGC) in instant tea soup and its intestinal degradation law. Both pH 2.0 and pH 7.0 decreased the antioxidant activity of tea soup, and the effect of acidic pH was greater. The addition of pepsin, TP and cate increased the antioxidant capacity of tea soup, while the addition of bile salt and trypsin decreased the FRAP value of tea soup. To sum up, the preparation of instant tea powder, pH and the phased action of digestive enzymes could affect the digestion stability of catechins in tea. By optimizing the extraction parameters of instant tea, the changes of catechins in tea can be reduced, and the influence of gastric acid environment during instant tea drinking can be avoided, so as to improve the bioavailability of catechins in tea leaves.

An Evaluation of the Impact of Cross-Boundary Innovation on Enhancing Brand Loyalty: An Example of Premium Payment Willingness in Novel-Tea Beverages

PENG Kang, YAN Pengxiang, LIN Mengxing, CHEN Fuqiao

Journal of Tea Science. 2025, 45(4): 712-726. doi:10.13305/j.cnki.jts.2025.04.002

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With the rapid development of the novel-tea beverage industry, market competition has significantly intensified. To enhance competitiveness, novel-tea beverage enterprises have increasingly adopted cross-border innovation strategies aimed at upgrading product quality, optimizing the consumer experience, and strengthening brand loyalty. However, the theoretical and empirical understanding of how cross-border innovation enhances brand loyalty is still limited. Utilizing quantitative empirical methods, this study investigated the impact of horizontal and vertical cross-border innovation on consumer brand loyalty based on survey data of 1 900 young novel-tea beverage consumers. The findings reveal that both forms of cross-border innovation contribute to strengthening brand loyalty, with upstream cultural integration within vertical cross-border innovation demonstrating the strongest effect. Furthermore, cross-border innovation primarily influences brand loyalty indirectly by satisfying consumers’ quality demands and enriching consumption experiences, with quality appeal serving as the core mediating mechanism. Additionally, the selection of cross-border innovation strategies is contingent upon enterprise positioning: high-end brands benefit more from horizontal and upstream cultural cross-border innovation, while mid-to-low-end brands achieve brand loyalty enhancement through scenario-based downward cross-border innovation. Based on the above conclusions, this paper proposed some countermeasures and suggestions on how to carry out cross-border innovation marketing.

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