Project description:The tea plant is an economically important woody beverage crop. The unique taste of tea is evoked by certain metabolites, especially catechin esters, whereas their precise formation mechanism in different cell types remains unclear. Here, a fast protoplast isolation method was established and the transcriptional profiles of 16,977 single cells from 1st and 3rd leaves were investigated. We first identified 78 marker genes based on six isolated tissues and constructed a transcriptome atlas, mapped developmental trajectories, and further delineated the distribution of different cell types during leaf differentiation, and genes associated with cell fate transformation. Interestingly, eight differently expressed genes were found to co-exist at four branch points. Genes involved in the biosynthesis of certain metabolites showed cell- and development-specific characteristics. An unexpected catechin ester glycosyltransferase was characterized for the first time in plants by a gene co-expression network in mesophyll cells. Thus, the first single-cell transcriptional landscape in woody crop leave was reported and a novel metabolism pathway of catechin esters in plants was discovered.
Project description:Senescence is initiated immediately in harvested tea leaves, and leads to physiological and biochemical changes, and could affects the final tea products. In the present work, we investigated the relationship between hormones and critical components in harvested tea leaves before withering, changes in hormones including abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), and critical components like catechins, theanine, and caffeine were analyzed. Significant changes in these substances were identified and ABA correlated with catechin in harvested tea leaves before withering. RNA-seq transcriptome analysis revealed dramatic differences between tea samples at 1 h and 2 h compared with those at 0 h. The patterns of these three critical components correlated with the expression profiles of differentially expressed genes (DEGs). Weighted correlation network analysis of co-expressed genes revealed that genes in the mediumpurple2 module correlated with ABA and catechins. The results of this study suggest that harvested tea leaves before withering undergo significant hormonal changes (ABA, JA, and SA) and ABA may participate in regulating catechin biosynthesis.
Project description:The tea plant is an economically important woody beverage crop. The unique taste of tea is evoked by certain metabolites, especially catechin esters, whereas their precise formation mechanism in different cell types remains unclear. Here, a fast protoplast isolation method was established and the transcriptional profiles of 16 977 single cells from 1st and 3rd leaves were investigated. We first identified 79 marker genes based on six isolated tissues and constructed a transcriptome atlas, mapped developmental trajectories and further delineated the distribution of different cell types during leaf differentiation and genes associated with cell fate transformation. Interestingly, eight differently expressed genes were found to co-exist at four branch points. Genes involved in the biosynthesis of certain metabolites showed cell- and development-specific characteristics. An unexpected catechin ester glycosyltransferase was characterized for the first time in plants by a gene co-expression network in mesophyll cells. Thus, the first single-cell transcriptional landscape in woody crop leave was reported and a novel metabolism pathway of catechin esters in plants was discovered.
Project description:Cysteine S-nitrosylation is a reversible protein post-translational modification and critically regulates the activity, localization and stability of proteins. Tea (Camellia sinensis (L.)) is one of the most thoroughly studied evergreen crop due to its broad non-alcoholic beverage and huge economic impact in the world. However, to date, little is known about the S-nitrosylome in this plant. Here, we performed a global analysis of cysteine S-nitrosylation in tea leaves. In total, 228 cysteine S-nitrosylation sites were identified in 191 proteins, representing the first extensive data on the S-nitrosylome in tea plants. These S-nitrosylated proteins were located in multiple subcellular compartments, especially in the chloroplast and cytoplasm. The analysis of functional enrichment and PPI network revealed that the S-nitrosylated proteins were mainly involved in carbon metabolism, especially in Calvin cycle and TCA cycle. These results suggested that S-nitrosylated proteins in tea leaves might play critical regulatory roles in the carbon metabolism. Overall, this study not only globally analyzed the functional annotation of cysteine S-nitrosylation in tea leaves, but also preliminarily provided the valuable information for further investigating the functions of cysteine S-nitrosylation in tea plants.
Project description:Recently, intensive global climate change has become a major factor impacting plant survival during the winter. Freezing cold temperatures during the winter and abnormal temperature fluctuations during the winter and early spring are the most harmful ambient factors threatening tea plant winter survival and currently cause marked economic losses in tea production. In this study, by simulating natural climate change, we established cold acclimation (CA) and rapid cold stress (after CA) conditions to comprehensively investigate the transcriptome changes involved in CA and rapid cold stress. Electrolyte leakage (EL) rate and expression profile clustering analyses confirmed that the experimental design was valid. Comparative transcription analysis identified many differentially expressed genes (DEGs) involved in both processes. Time course and pathway enrichment analyses further revealed the physiological changes that occur during the initial period of CA and the cell wall changes that occur throughout the entire CA process; these changes play crucial roles in increasing freezing tolerance during this process. Compared with CA, different cold response mechanisms were rapidly activated under cold stress; however, the subsequent accumulation of reactive oxygen species, which affect multiple aspects, caused by freezing cold could be the harshest factor impairing tea leaves. Moreover, we investigated 60 DEGs shared by both processes and highlighted the importance of KCSs, HXXXD-type acyl-transferase family proteins, NAC080, SWEETs and ENOs in the responses to various cold conditions. These results greatly improve our knowledge of cold response mechanisms in tea plants and provide meaningful information for functional studies investigating cold tolerance-related genes.
Project description:This project is based on the extension of the single cell transcriptomics atlas of mouse development towards E9.5. Inference of cell differentiation trajectories was carried out using Waddington-Optimal Transport, and the resulting computational reconstruction was contrasted with grafting experiments as well as complementary scRNA-seq experiments.
Project description:Background: Lysine crotonylation (Kcr), as a novel evolutionarily conserved type of PTM, is ubiquitous and essential in cell biology. However, its functions in tea plant, an important beverage crop, are largely unknown. Our study firstly attempted to describe Kcr proteins in tea leaves under NH4+ deficiency/resupply, and provided significant insights into exploring the physiological role of Kcr in plants for N utilization. Results: We performed the global analysis of crotonylome in tea plants under NH4+ deficiency/resupply using high-resolution LC-MS/MS coupled with highly sensitive immune-antibody. A total of 2288 kcr sites on 971 proteins were identified, of which contained in 15 types of Kcr motifs. Most of Kcr proteins were located in chloroplast and cytoplasm. 120 and 151 Kcr proteins were significantly changed at 3 hours and 3days of NH4+ resupply, respectively. Bioinformatics analysis showed that differentially expressed Kcr proteins participated in diverse biological processes such as photosynthesis, carbon fixation and amino acid metabolism, suggesting Kcr plays important roles in these processes. Interestingly, a large number of enzymes were crotonylated, and the activity and Kcr level of these enzymes changed significantly after NH4+ resupply, indicating a potential function of Kcr in the regulation of enzyme activities. Moreover, the protein-protein interaction analysis revealed that the diverse interactions of identified Kcr proteins mainly involved in photosynthesis, carbon fixation, amino acid metabolism and ribosome. Conclusions: The results suggested that lysine crotonylated proteins might play regulating roles in metabolic process in tea leaves under NH4+ deficiency/resupply. The critical regulatory roles mainly involved in diverse aspects of primary metabolic processes, especially in photosynthesis, carbon fixation and amino acid metabolism. The provided data may serve as important resources for exploring the physiological, biochemical, and genetic role of lysine crotonylation in tea plants.
Project description:This project is based on the extension of the single cell transcriptomics atlas of mouse development towards E9.5. Inference of cell differentiation trajectories was carried out using Waddington-Optimal Transport, and the resulting computational reconstruction was contrasted with grafting experiments as well as complementary scRNA-seq experiments. This data submission refers to the grafting experiments.
Project description:In field conditions, tea plants are often exposed to drought stress, which has profound effects on the growth and development of tea plants. However, most studies on tea plants in response to drought stress focused on single gene or protein expression, and transcriptome or proteome profiles, the impact of drought stress on ubiquitination in proteins remains unearthed. We performed a global profile of ubiquitinated (Kub) proteins in tea leaves under drought stress. In total, 1,409 lysine Kub sites in 781 proteins were identified, of which 14 sites in 12 proteins were up-regulated and 123 sites in 91 proteins were down-regulated compared with drought and control. Furthermore, we analyzed the Kub proteins related to ubiquitin-mediated proteolysis, catechins biosynthesis, and carbohydrate and amino acid metabolism in tea leaves under drought stress. The results indicated that many Kub proteins involved in ubiquitin-mediated proteolysis played important roles in protein degradation. Several Kub proteins related to catechins biosynthesis were positively correlated with each other because of their co-expression and co-localization. Our study preliminarily revealed the global profiling of Kub proteins in metabolic pathways and provided an important resource for further study on the functions of Kub proteins in tea plants under drought stress.