Metabolism of methionine and biosynthesis of caffeine in the tea plant (Camellia sinensis L.).
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ABSTRACT:
SUBMITTER: Suzuki T
PROVIDER: S-EPMC1164219 | biostudies-other | 1976 Nov
REPOSITORIES: biostudies-other
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Project description:BACKGROUND:Catechins, caffeine, and theanine as three important metabolites in the tea leaves play essential roles in the formation of specific taste and shows potential health benefits to humans. However, the knowledge on the dynamic changes of these metabolites content over seasons, as well as the candidate regulatory factors, remains largely undetermined. RESULTS:An integrated transcriptomic and metabolomic approach was used to analyze the dynamic changes of three mainly metabolites including catechins, caffeine, and theanine, and to explore the potential influencing factors associated with these dynamic changes over the course of seasons. We found that the catechins abundance was higher in Summer than that in Spring and Autumn, and the theanine abundance was significantly higher in Spring than that in Summer and Autumn, whereas caffeine exhibited no significant changes over three seasons. Transcriptomics analysis suggested that genes in photosynthesis pathway were significantly down-regulated which might in linkage to the formation of different phenotypes and metabolites content in the tea leaves of varied seasons. Fifty-six copies of nine genes in catechins biosynthesis, 30 copies of 10 genes in caffeine biosynthesis, and 12 copies of six genes in theanine biosynthesis were detected. The correlative analysis further presented that eight genes can be regulated by transcription factors, and highly correlated with the changes of metabolites abundance in tea-leaves. CONCLUSION:Sunshine intensity as a key factor can affect photosynthesis of tea plants, further affect the expression of major Transcription factors (TFs) and structural genes in, and finally resulted in the various amounts of catechins, caffeine and theaine in tea-leaves over three seasons. These findings provide new insights into abundance and influencing factors of metabolites of tea in different seasons, and further our understanding in the formation of flavor, nutrition and medicinal function.
| S-EPMC7322862 | biostudies-literature
Project description:The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control. However, little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants. Here, we reported that TCP TFs are involved in both catechin biosynthesis and leaf development. An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production. CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat (MBW) complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase (CsANS1) and anthocyanidin reductase (CsANR1). Four types of microRNA/target modules, miR319b/CsTCP3-4, miR164b/CsCUC, miR396/CsGRF-GIF, and miR165b/HD-ZIPIII ones, were also identified and characterized for their functions in the regulation of the development of tea plant shoot tips and leaf shape. The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different tea plant varieties. Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b (miR319b), which targets the transcripts of CsTCP3 and CsTCP4. Thus, CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis. Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.
| S-EPMC8087681 | biostudies-literature
Project description:1. The tRNA methyltransferase activity in vitro of leaves, cotyledons and roots of 85-day-old tea seedlings was studied. 2. The activity of extracts prepared from tea leaves with Polycar AT (insoluble polyvinylpyrrolidine) had optimum pH7.7 and was greatly influenced by thiol compounds, but only slightly by metal ions and ammonium acetate. 3. The activities of extracts, expressed per mg of protein, were as follows: roots greater than leaves greater than cotyledons. The only methylated base isolated after incubation with these preparations was 1-methyladenine. 4. The results did not support the view of involvement of methylation of nucleic acids in caffeine biosynthesis in tea plants. In contrast, it is suggested that theophylline is synthesized from the specific methylated precursor in nucleic acids, namely 1-methyladenylic acid, via 1-methylxanthine.
| S-EPMC1164220 | biostudies-other
Project description:1. Methods for the separation and determination of the polyphenolic components of the tea plant by thin-layer chromatography and colorimetric reactions have been devised. 2. High concentrations of catechins, flavonols and depsides were found to be restricted to the young vegetative and floral shoots, whereas leucoanthocyanins or flavylogens were characteristic of the more bulky axial tissues of the plant. 3. In the young shoots cell growth was correlated with an increasing degree of flavonoid B-ring hydroxylation. 4. Maximal flavylogen concentrations occurred in the outer protective layers of stem and of seed coat. 5. Mature leaves were shown to contain derivatives of the flavones apigenin and luteolin. 6. Developing seedlings showed a steady increase in polyphenol complexity; flavylogens were concentrated at shoot and root apices and accumulated at the stem base. 7. It is postulated that the flavanols (leucoanthocyanins and catechins), because they can co-polymerize, are of use to the plant for protection of wood and bark against infection and decay.
| S-EPMC1184764 | biostudies-other
Project description:BackgroundMajor secondary metabolites, including flavonoids, caffeine, and theanine, are important components of tea products and are closely related to the taste, flavor, and health benefits of tea. Secondary metabolite biosynthesis in Camellia sinensis is differentially regulated in different tissues during growth and development. Until now, little was known about the expression patterns of genes involved in secondary metabolic pathways or their regulatory mechanisms. This study aimed to generate expression profiles for C. sinensis tissues and to build a gene regulation model of the secondary metabolic pathways.ResultsRNA sequencing was performed on 13 different tissue samples from various organs and developmental stages of tea plants, including buds and leaves of different ages, stems, flowers, seeds, and roots. A total of 43.7 Gbp of raw sequencing data were generated, from which 347,827 unigenes were assembled and annotated. There were 46,693, 8446, 3814, 10,206, and 4948 unigenes specifically expressed in the buds and leaves, stems, flowers, seeds, and roots, respectively. In total, 1719 unigenes were identified as being involved in the secondary metabolic pathways in C. sinensis, and the expression patterns of the genes involved in flavonoid, caffeine, and theanine biosynthesis were characterized, revealing the dynamic nature of their regulation during plant growth and development. The possible transcription factor regulation network for the biosynthesis of flavonoid, caffeine, and theanine was built, encompassing 339 transcription factors from 35 families, namely bHLH, MYB, and NAC, among others. Remarkably, not only did the data reveal the possible critical check points in the flavonoid, caffeine, and theanine biosynthesis pathways, but also implicated the key transcription factors and related mechanisms in the regulation of secondary metabolite biosynthesis.ConclusionsOur study generated gene expression profiles for different tissues at different developmental stages in tea plants. The gene network responsible for the regulation of the secondary metabolic pathways was analyzed. Our work elucidated the possible cross talk in gene regulation between the secondary metabolite biosynthetic pathways in C. sinensis. The results increase our understanding of how secondary metabolic pathways are regulated during plant development and growth cycles, and help pave the way for genetic selection and engineering for germplasm improvement.
| S-EPMC4518527 | biostudies-literature
Project description:As the main flavor components of tea, the contents of epigallocatechin-3-gallate (EGCG), theanine and caffeine are regulated by ambient temperature. However, whether the biosynthesis of EGCG, theanine and caffeine in response to temperature is regulated by endogenous hormones and its mechanism is still unclear. In this study, tea cuttings cultivated in the phytotron which treated at different temperatures 15℃, 20℃, 25℃ and 30℃, respectively. The UPLC and ESI-HPLC-MS/MS were used to determine the contents of EGCG, theanine, caffeine and the contents of phytohormones in one leaf and a bud. The results showed that indoleacetic acid (IAA), gibberellin 1(GA1) and gibberellin 3 (GA3) were significantly correlated with the content of EGCG; Jasmonic acid (JA), jasmonate-isoleucine (JA-Ile) and methyl jasmonate (MeJA) were strongly correlated with theanine content; IAA, GA1 and gibberellin 4 (GA4) were significantly correlated with caffeine content at different temperatures. In order to explore the internal intricate relationships between the biosynthesis of these three main taste components, endogenous hormones, and structural genes in tea plants, we used multi-omics and multidimensional correlation analysis to speculate the regulatory mechanisms: IAA, GA1 and GA3 up-regulated the expressions of chalcone synthase (CsCHS) and trans-cinnamate 4-monooxygenase (CsC4H) mediated by the signal transduction factors auxin-responsive protein IAA (CsIAA) and DELLA protein (CsDELLA), respectively, which promoted the biosynthesis of EGCG; IAA, GA3 and GA1 up-regulated the expression of CsCHS and anthocyanidin synthase (CsANS) mediated by CsIAA and CsDELLA, respectively, via the transcription factor WRKY DNA-binding protein (CsWRKY), and promoted the biosynthesis of EGCG; JA, JA-Ile and MeJA jointly up-regulated the expression of carbonic anhydrase (CsCA) and down-regulated the expression of glutamate decarboxylase (CsgadB) mediated by the signal transduction factors jasmonate ZIM domain-containing protein (CsJAZ), and promoted the biosynthesis of theanine; JA, JA-Ile and MeJA also jointly inhibited the expression of CsgadB mediated by CsJAZ via the transcription factor CsWRKY and AP2 family protein (CsAP2), which promoted the biosynthesis of theanine; IAA inhibited the expression of adenylosuccinate synthase (CspurA) mediated by CsIAA via the transcription factor CsWRKY; GA1 and gibberellin 4 (GA4) inhibited the expression of CspurA mediated by CsDELLA through the transcription factor CsWRKY, which promoted the biosynthesis of caffeine. In conclusion, we revealed the underlying mechanism of the biosynthesis of the main taste components in tea plant in response to temperature was mediated by hormone signal transduction factors, which provided novel insights into improving the quality of tea.
| S-EPMC10076774 | biostudies-literature
Project description:1. A method for the extraction of 5-dehydroshikimate reductase (EC 1.1.1.25) from tea plant tissues in an active soluble state has been developed. It is dependent on the use, in the extraction medium, of an insoluble polyphenol adsorbent (Polyclar AT), which prevents the polyphenols present from precipitating all the proteins. 2. The enzyme has the following properties: pH optima at pH10.1 in glycine-sodium hydroxide buffer and at pH7.7 in tris-hydrochloric acid buffer; K(m) (NADP) 32mum and K(m) (shikimate) 0.43mm; and NADP-specificity. It was completely inhibited by 0.33mm-p-chloromercuribenzoate and this inhibition was completely reversed by 10mm-cysteine. Iodoacetate and arsenite inhibited the enzyme to a smaller extent. 3. The specific activity of the enzyme was higher in the parts of the actively growing shoot tips (third leaf>stem>second leaf>first leaf>bud) than in the mature leaves. However, the mature leaves had the greatest total activity. 4. The importance of these findings with respect to flavanol biosynthesis in tea plants is discussed.
| S-EPMC1264822 | biostudies-other
Project description:Theanine (thea) is a unique non-protein amino acid in tea plant (Camellia sinensis) and one of the most important small molecular compounds for tea quality and health effects. The molecular mechanism that maintains thea biosynthesis is not clear but may be reflected in complicated biological networks as other secondary metabolites in plants. We performed an integrative transcriptomic analysis of tea seedlings bud and leave over the time-course of ethylamine (EA) treatment that activated thea pathway. We identified 54 consistent differentially expressed genes (cDEGs, 25 upregulated and 29 downregulated) during thea activation. Gene Ontology (GO) functional enrichment analysis of upregulated genes and downregulated genes showed that they may function as a cascade of biological events during their cooperative contribution to thea biosynthesis. Among the total cDEGs, a diversity of functional genes (e.g., enzymes, transcription factors, transport and binding proteins) were identified, indicating a hierarchy of gene control network underlying thea biosynthesis. A gene network associated with thea biosynthesis was modeled and three interconnected gene functional modules were identified. Among the gene modules, several topologically important genes (e.g., CsBCS-1, CsRP, CsABC2) were experimentally validated using a combined thea content and gene expression analysis. Collectively, we presented here for the first time a comprehensive landscape of the biosynthetic mechanism of thea controlled by a underling gene network, which might provide a theoretical basis for the identification of key genes that contribute to thea biosynthesis.
| S-EPMC7482930 | biostudies-literature
Project description:Genome variation not only plays an important role in plant phenotypic modeling and adaptive evolution, but also enhances population genetic diversity and regulates gene expression. The tea tree (Camellia sinensis) has a large genome (~ 3.0 Gb), making the identification of genome-wide variants time-consuming and expensive. With the continuous publication of a large number of different types of population sequencing data, there is a lack of an open platform to integrate these data and identify variants in the tea plant genome.To integrate the genetic variation confidence in the tea plant population genome, 238 whole-genome resequencing, 213 transcriptome sequencing, and 96 hybrid F1 individuals with a total of more than 20 Tb were collected for mutation site identification. Based on these variations information, we constructed the first tea tree variation web service database TeaPVs ( http://47.106.184.91:8025/ and http://liushang.top:8025/ ). It supports users to search all SNP, Indel, SV mutations and SSR/Polymorphic SSR sequences by location or gene ID. Furthermore, the website also provides the functions of gene expression search of different transcriptome, sequence blast, sequence extraction of CDS and mutation loci, etc.The features of the TeaPVs database make it a comprehensive tea plant genetic variation bioinformatics platform for researchers, and will also be helpful for revealing new functional mutations in the tea plant genome and molecular marker-assisted breeding.
| S-EPMC9632082 | biostudies-literature
Project description:The phytochrome-interacting factors (PIFs) proteins belong to the subfamily of basic helix-loop-helix (bHLH) transcription factors and play important roles in chloroplast development and chlorophyll biosynthesis. Currently, knowledge about the PIF gene family in Camellia sinensis remains very limited. In this study, seven PIF members were identified in the C. sinensis genome and named based on homology with AtPIF genes in Arabidopsis thaliana. All C. sinensis PIF (CsPIF) proteins have both the conserved active PHYB binding (APB) and bHLH domains. Phylogenetic analysis revealed that CsPIFs were clustered into four groups-PIF1, PIF3, PIF7, and PIF8-and most CsPIFs were clustered in pairs with their corresponding orthologs in Populus tremula. CsPIF members in the same group tended to display uniform or similar exon-intron distribution patterns and motif compositions. CsPIF genes were differentially expressed in C. sinensis with various leaf colors and strongly correlated with the expression of genes involved in the chlorophyll metabolism pathway. Promoter analysis of structural genes related to chlorophyll metabolism found DNA-binding sites of PIFs were abundant in the promoter regions. Protein-protein interaction networks of CsPIFs demonstrated a close association with phytochrome, PIF4, HY5, TOC1, COP1, and PTAC12 proteins. Additionally, subcellular localization and transcriptional activity analysis suggested that CsPIF3b was nuclear localized protein and possessed transcriptional activity. We also found that CsPIF3b could activate the transcription of CsHEMA and CsPOR in Nicotiana benthamiana leaves. This work provides comprehensive research of CsPIFs and would be helpful to further promote the regulation mechanism of PIF on chlorophyll metabolism in C. sinensis.
| S-EPMC8539375 | biostudies-literature