Physiological and transcriptomic analyses reveal tea plant (Camellia sinensis L.) adapts to extreme freezing stress during winter by regulating cell wall structure.

Tea plants grown in high-latitude areas are often damaged by extreme freezing temperatures in winter, leading to huge economic losses. Here, the physiological and gene expression characteristics of two tea cultivars (Xinyang No. 10 (XY10), a freezing-tolerant cultivar and Fudingdabaicha (FDDB), a freezing-sensitive cultivar) during overwintering in northern China were studied to better understand the regulation mechanisms of tea plants in response to natural freezing stress.

Dynamic Changes of Volatile Compounds during the Xinyang Maojian Green Tea Manufacturing at an Industrial Scale.

Xinyang Maojian (XYMJ) is one of the premium green teas and originates from Xinyang, which is the northernmost green tea production area in China. The special geographic location, environmental conditions, and manufacturing process contribute to the unique flavor and rich nutrition of XYMJ green tea. Aroma is an important quality indicator in XYMJ green tea.

Genome-wide identification of PME gene family and expression of candidate genes associated with aluminum tolerance in tea plant (Camellia sinensis).

Background: The major aluminum (Al) detoxication mechanism of tea plant (Camellia sinensis), as an Al hyperaccumulator plant, is the fixation of almost 70% of Al in the cell walls. Pectin is the primary constituent of cell walls, a degree of methylation of pectin polysaccharides regulated by the pectin methylesterase (PME) genes can greatly affect the Al binding capacity. The knowledge on PME gene family in tea plant is still poor.

Identification of aroma-active compounds responsible for the floral and sweet odors of Congou black teas using gas chromatography-mass spectrometry/olfactometry, odor activity value, and chemometrics.

Background: Floral and sweet odors are two typical characteristic aromas of Congou black tea, but their aroma-active compounds are still unclear. Characterizing the key aroma-active compounds can provide a theoretical foundation for the practical aroma quality evaluation of Congou black tea and directional processing technology of high-quality black tea with floral or sweet odors. Gas chromatography-olfactometry (GC-O) combined with odor activity value (OAV) is often used to screen key aroma-active substances, but the interaction between aroma components and their impact on the overall sensory quality is ignored.

The performance of water-soluble fluoride transformation in soil-tea-tea infusion chain system and the potential health risk assessment.

Background: Water-soluble fluoride (WS-F) can be absorbed directly by tea plants from soil and comprises a major source of dietary F in tea consumers. To reveal the WS-F accumulation in tea leaves and assess WS-F health risks, 70 sets of samples including tea leaves at three maturity stages and corresponding topsoil were collected from Xinyang, China. The WS-F contents in tea samples and pH values in soil samples were determined.

New insights into the effect of fermentation temperature and duration on catechins conversion and formation of tea pigments and theasinensins in black tea.

Background: The phenol oxidative pathway during fermentation remains unclear. To elucidate the effect of fermentation on phenol conversion, we investigated the effects of fermentation temperature and duration on the conversion of catechins and the formation of theasinensins (TSs), theaflavins (TFs), thearubigins (TRs), and theabrownins (TBs).

Results: During fermentation, TSs formation increased initially and then decreased.

Region identification of Xinyang Maojian tea using UHPLC-Q-TOF/MS-based metabolomics coupled with multivariate statistical analyses.

Xinyang Maojian tea is a kind of famous roasted green tea produced in the middle of China. Ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UHPLC-Q-TOF/MS)-based metabolomics coupled with multivariate statistical analyses, including principal component analysis (PCA) and hierarchical cluster analysis (HCA), were carried out in XMMJTs collected from Luoshan, Shangcheng, and Shihe Counties, respectively. Additionally, seven catechins, four flavonoids, two purine alkaloids, and gallic acid contents were determined by HPLC.

Untargeted metabolomics coupled with chemometrics approach for Xinyang Maojian green tea with cultivar, elevation and processing variations.

The quality and flavor of green tea can be affected by various factors, which are closely related to the metabolite composition of tea. In this study, 66 Xinyang Maojian tea (XYMJ) samples produced by four cultivars, grown in different elevations and manufactured by different processing methods were analyzed by untargeted ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and chemometrics. 1912 ion features were detected and 95 metabolites were identified tentatively through a customized in-house library.

Residue pattern of chlorpyrifos and its metabolite in tea from cultivation to consumption.

Background: Chlorpyrifos (CPF) is a broad-spectrum organophosphorus pesticide widely used to control tea geometrid (Ectropis oblique) and tea green leafhoppers (Empoasca pirisuga Matsumura) in tea trees. The major metabolite of CPF in water, plants, and animals is 3,5,6-trichloro-2-pyridinol, which is more toxic than CPF. However, the dissipation pattern of CPF in tea is unknown.

Utilization of microRNAs and their regulatory functions for improving biotic stress tolerance in tea plant [ (L.) O. Kuntze].

MicroRNAs play a central role in responses to biotic stressors through their interactions with their target mRNAs. Tea plant ( L.), an important beverage crop, is vulnerable to tea geometrid and anthracnose disease that causes considerable crop loss and tea production worldwide.

Genome-wide characterization of tea plant (Camellia sinensis) Hsf transcription factor family and role of CsHsfA2 in heat tolerance.

Background: Heat stress factors (Hsfs) play vital roles in signal transduction pathways operating in responses to environmental stresses. However, Hsf gene family has not been thoroughly explored in tea plant (Camellia sinensis L.).

The involvements of calcium-dependent protein kinases and catechins in tea plant [Camellia sinensis (L.) O. Kuntze] cold responses.

Temperature is one of the most important environmental factors limiting tea plant growth and tea production. Previously we reported that both Ca and ROS signals play important roles in tea plant cold acclimation. Here, we identified 26 CsCPK transcripts, analyzed their phylogenetic and sequence characters, and detected their transcriptions to monitor Ca signaling status.

Transcriptome analysis of differentially expressed genes involved in selenium accumulation in tea plant (Camellia sinensis).

Tea plant (Camellia sinensis) has strong enrichment ability for selenium (Se). Selenite is the main form of Se absorbed and utilized by tea plant. However, the mechanism of selenite absorption and accumulation in tea plant is still unknown.