Search Results (5)

The vital role of arbuscular mycorrhizal (AM) fungi in tea plant growth is well established; however, the mechanisms underlying how increasing cultivation chronosequence (CC) influences AM fungal distribution remain unclear. An investigation was conducted to investigate the temporal dynamics of AM fungal indices and soil properties across a 100-year tea CC (10-, 30-, 60-, and 100-year CC) in Xinyang Maojian tea (Camellia sinensis L.) plantations (Xinyang, Henan Province, China). Principal coordinate analysis was conducted to reveal the significant reorganization of AM fungal indices during early-to-mid stages (PCoA1: 89.2%, p < 0.05), with triphasic development. Mycorrhizal colonization (MC), hypha biomass (hypha), and spore density (SD) surged by 100% during 10–30 years; SD peaked at 60 years (164 spores g⁻¹) before declining, while glomalin-related soil protein (GRSP) accumulated significantly only at 100 years (p < 0.05). Concurrently, soil acidification (pH decreased from 6.37 to 4.84) and phosphorus depletion (AP from 119.6 mg kg⁻¹ to 32 mg kg⁻¹) intensified by 60 years, contrasting with the significant accumulations of soil organic organisms (SOM) (from 10.6 g kg⁻¹ to 36.4 g kg⁻¹), electrical conductivity (EC) (from 0.019 to 0.050 mS·cm⁻¹), and microaggregate accumulation (MAR) (from 25.8% to 40.3%) during the period. The linear regression model was performed to validate the significant effects (p < 0.05) of CC on the AM indices (MC, SD, hypha, and GRSP) and soil physiochemical characteristics (EC, moisture, and SOM). Variance partitioning attributed 97.4% of the total variation, while interactions among cultivation ages, nutrient characteristics (SOM and AP), and non-nutrient characteristics (pH, EC, moisture, and aggregates) accounted for 23.0%. To identify the driving factors of AM fungi indices, Pearson correlation and redundancy analysis (RDA) were performed, and EC (26.5%) and pH (20.9%) were identified as the paramount regulators of hyphal integrity and colonization efficiency. It was found that 60 years worked as a critical transition point for targeted interventions (e.g., organic amendments and pH buffering) to mitigate rhizosphere dysfunction and optimize mycorrhizal services in perennial monocultures. Full article

The health benefits of tea are primarily attributed to its chemical composition, particularly phenolic compounds. As a renowned tea from Guangdong, China, Xianhu tea (XHT) has not been thoroughly studied in terms of its phenolic composition or health-promoting properties. This study characterized the phenolic compounds in Xianhu tea water extract (XHT) using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and evaluated its antioxidant activity in vitro. Furthermore, the effects of XHT extracts on reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), lipofuscin levels, and lifespan in Caenorhabditis elegans were assessed, alongside their modulation of aging-related genes. Compared with Xinyang Maojian tea water extract (XYMJ) and Yingde black tea water extract (YDBT), XHT exhibited a significantly higher polyphenol content, with 23 phenolic compounds identified as characteristic markers. XHT demonstrated superior 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) inhibition capacities, the greatest reductions in ROS, MDA, and lipofuscin levels, and the highest upregulation of SOD and CAT activities. The lifespan was 23.50% and 21.07% significantly longer than nematodes in the control group. Moreover, XHT modulated 13 aging-related genes, which strongly correlated with the 23 identified phenolic compounds. The research results of the above indicators were all obtained without affecting the normal feeding and reproductive capabilities of C. elegans. These findings suggest that these phenolics are the key bioactive components responsible for the anti-aging effects of XHT. Full article

Xinyang Maojian (XYMJ) tea is one of the world’s most popular green teas; the development of new sprouts directly affects the yield and quality of tea products, especially for XYMJ, which has hairy tips. Here, we used transcriptome and small RNA sequencing to identify mRNAs and miRNAs, respectively, involved in regulating leaf development in different plant tissues (bud, leaf, and stem). We identified a total of 381 conserved miRNAs. Given that no genomic data for XYMJ green tea are available, we compared the sequencing data for XYMJ green tea with genomic data from a closely related species (Tieguanyin) and the Camellia sinensis var. sinensis database; we identified a total of 506 and 485 novel miRNAs, respectively. We also identified 11 sequence-identical novel miRNAs in the tissues of XYMJ tea plants. Correlation analyses revealed 97 miRNA–mRNA pairs involved in leaf growth and development; the csn-miR319-2/csnTCP2 and miR159–csnMYB modules were found to be involved in leaf development in XYMJ green tea. Quantitative real-time PCR was used to validate the expression levels of the miRNAs and mRNAs. The miRNAs and target genes identified in this study might shed new light on the molecular mechanisms underlying the regulation of leaf development in tea plants. Full article

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. In order to illustrate the aroma of XYMJ green tea, the key odorants in XYMJ green tea and their dynamic changes during the manufacturing processes were analyzed by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 73 volatile compounds of six different chemical classes were identified in the processed XYMJ green tea samples, and the manufacturing processes resulted in the losses of total volatile compounds. Among the identified volatile compounds, twenty-four aroma-active compounds, such as trans-nerolidol, geranylacetone, nonanal, (+)-δ-cadinene, linalool, (Z)-jasmone, cis-3-hexenyl butyrate, cis-3-hexenyl hexanoate, methyl jasmonate, and β-ocimene, were identified as the key odorants of XYMJ green tea based on odor activity value (OAV). The key odorants are mainly volatile terpenes (VTs) and fatty acid-derived volatiles (FADVs). Except for (+)-δ-cadinene, copaene, cis-β-farnesene, (Z,E)-α-farnesene and phytol acetate, the key odorants significantly decreased after fixing. The principal coordinate analysis (PCoA) and the hierarchical cluster analysis (HCA) analyses suggested that fixing was the most important manufacturing process for the aroma formation of XYMJ green tea. These findings of this study provide meaningful information for the manufacturing and quality control of XYMJ green tea. Full article

Xinyang Maojian (XYMJ) green tea is one of the top ten teas in China, and the consumers prefer spring tea due to its umami taste and pleasurable aroma. However, the knowledge about temporal variation of the volatile compounds in XYMJ green teas harvested during different seasons is very limited. In the present work, the main non-volatile compounds that endowed the taste and volatile compounds responsible for the aroma in XYMJ green teas harvested during the spring and autumn seasons were determined. The average contents of free amino acids (FAA) were significantly higher and gradually declined in the spring teas, whereas the caffeine was significantly lower and gradually increased in the spring teas. A total of 39 volatile compounds of six chemical classes were detected in XYMJ green teas, and they displayed various change trends during the spring and autumn seasons, among which 15 volatile compounds were identified as the key odorants based on odor activity value (OAV). The highest OAV of 2195.05 was calculated for the violet-like smelling trans-β-ionone followed by decanal, nonanal, dimethyl sulfide, linalool, geraniol and naphthalene. The OAVs of geraniol, (Z)-3-hexenyl hexanoate, heptanal, benzaldehyde and hexanal in XYMJ spring teas were higher than XYMJ autumn teas. The hierarchical clustering analysis indicated that XYMJ green teas were divided into three clusters and the quality of XYMJ green teas changed greatly within spring season. Harvest season is a crucial factor affecting the flavor quality of XYMJ green teas. Full article