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5-Dehydroshikimate reductase in the tea plant (Camellia sinensis L.). Properties and distribution.

ABSTRACT: 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.

SUBMITTER: Sanderson GW

PROVIDER: S-EPMC1264822 | biostudies-other | 1966 Jan

REPOSITORIES: biostudies-other

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The distribution of polyphenols in the tea plant (Camellia sinensis L.).

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

Effects of light and darkness on polyphenol distribution in the tea plant (Camellia sinensis L.).

Project description:1. Flavonoid synthesis was able to proceed in darkness in young shoots and seedlings of the tea plant, but was increased by light. 2. The initial effect of darkness was to inhibit synthesis of the A ring or its linkage to the phenylpropane moiety of the flavonoid, but later the hydroxylation state of the flavanols was affected, leading to smaller proportions of gallocatechins and of complex leucoanthocyanins. 3. The esterification of catechins with gallic acid was less affected, so that the ratio of catechin gallates to simple catechins also increased. 4. The flavylogen content of darkened stems, especially in seedlings, was much less decreased than that of leaves; however, a short subsequent light-treatment caused an increase in polymerization.

| S-EPMC1184767 | biostudies-other

The separation and distribution of simple and condensed leucoanthocyanins of the tea plant (Camellia sinensis L.).

Project description:1. Leucoanthocyanin monomers of high mobilities in aqueous solvents on thinlayer chromatograms, assumed to be structurally simple, were characteristic of mature bulky tissues, whereas members of lower mobility were confined to young vegetative and floral tissues. 2. Flavylogens were separated by gel filtration on Sephadex columns into monomeric, oligomeric and polymeric fractions. 3. The polymeric fraction from young brown stems was heterogeneous, one-half having a molecular weight of about 3400, one-third a molecular weight between 3600 and 17000, and the remainder a molecular weight of over 17000. 4. Leaves had low flavylogen concentrations; only monomers were present. Stem tissues were rich in polymers, which increased with the age of the young stem and decreased inwards through the wood. The maximal flavylogen concentrations were in the phloem and cambium from mature stems, where all three fractions were richly present. The periderm tissue and, to a lesser extent, the seed coat were characterized by a very high polymer/monomer ratio, exhibiting a much higher degree of polymerization than the wood. Root tissues contained high concentrations of monomers. 5. In general, there was an inverse correlation between the extent of polymerization and the complexity of the monomers present. 6. The results are in favour of the thesis that the function of the flavanols is, after polymerization to condensed tannins, to impregnate dead structural tissues and thereby to protect them from infection and decay.

| S-EPMC1184765 | biostudies-other

Metabolism of methionine and biosynthesis of caffeine in the tea plant (Camellia sinensis L.).

Project description:1. Caffeine biosynthesis was studied by following the incorporation of 14C into the products of L-[Me-14C]methionine metabolism in tea shoot tips. 2. After administration of a 'pulse' of L-[Me-14C]methionine, almost all of the L-[Me-14C]methionine supplied disappeared within 1 h, and 14C-labelled caffeine synthesis increased throughout the experimental periods, whereas the radioactivities of an unknown compound and theobromine were highest at 3 h after the uptake of L-[Me-14C]methionine, followed by a steady decrease. There was also slight incorporation of the label into 7-methylxanthine, serine, glutamate and aspartate, disappearing by 36 h after the absorption of L-[Me-14C]methionine. 3. The radioactivities of nucleic acids derived from L-[Me-14C]methionine increased rapidly during the first 12 h incubation period and then decreased steadily. Sedimentation analysis of nucleic acids by sucrose-gradient centrifugation showed that methylation of nucleic acids in tea shoot tips occurred mainly in the tRNA fraction. The main product among the methylated bases in tea shoot tips was identified as 1-methyladenine. 4. The results indicated that the purine ring in caffeine is derived from the purine nucleotides in the nucleotide pool rather than in nucleic acids. A metabolic scheme to show the production of caffeine and related methylxanthines from the nucleotides in tea plants is discussed.

| S-EPMC1164219 | biostudies-other

Effect of fluoride treatment on gene expression in tea plant (Camellia sinensis).

Project description:Tea plant is a typical fluorine (F) accumulator. F concentration in mature tea leaves is several hundred times higher than that in normal field crops. Long-term consumption of teas with high level F will increase the risks of dental and skeletal fluorosis. The mechanism of F accumulation in tea stands unclear. RNA-Seq and digital gene expression (DGE) techniques were used to investigate the effect of F on the differential expressions of transcriptome in tea plant. The results showed that F content in mature tea leaves was increased with increase in F concentration of cultural solution and duration of F treatment time. Based on comparison with data of GO, COG, KEGG and Nr databases, 144 differentially expressed unigenes with definite annotation were identified. Real-time reverse transcription PCR (qRT-PCR) was used to validate the effect of F on expression of 5 unigenes screened from the 144 unigenes. F treatment induced the expression of defense genes such as receptor-like kinases (RLKs) and U-box domain-containing protein. Based on the present study, F uptake is considered to be related to calcium-transporting ATPase, especially autoinhibited Ca2+ ATPase (ACAs) which was activated by the RLKs and worked as a carrier in uptake of F by tea plant.

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Identification of conserved and species-specific microRNAs in tea plant (Camellia sinensis) by deep sequencing

Project description:In this study, it is noticeable that 32 tea-specific miRNAs were confirmed on the base of genome survey, using deep sequencing and microarray hybridization, and many miRNAs might associate with secondary metabolites synthesis. Leaves, buds and roots were collected

2016-03-14 | E-GEOD-68267 | biostudies-arrayexpress

The purification and some properties of the polyphenol oxidase from tea (Camellia sinensis L.).

Project description:1. Polyphenol oxidase (EC 1. 10. 3.-) from the shoots of the tea plant was purified about 5000-fold on a dry-weight basis. 2. At an intermediate stage of purification four soluble yellow fractions were obtained. They are believed to represent complexes of a basic enzyme protein with acidic phenolic oxidation products and nucleic acids. After removal of the complex-forming materials the fractions were blue and similar to each other. About 40% of the activity could not be extracted from the acetone-dried powder. 3. Each of the four blue fractions was resolved further into two species, A and B. The following results refer to species A. 4. The enzyme showed absorption maxima at 279mmu (E(1%) (1cm.), 13.5) and 611mmu (E(1%) (1cm.), 0.84) with a shoulder at 330mmu. The enzyme was bleached by substrate under anaerobic conditions and the colour was restored by oxygen. 5. The molecular weight measured by sedimentation and diffusion was 144000+/-16000. The copper content was 0.32% (w/w). 6. Kinetic constants are given for a number of substrates and inhibitors, including the natural substrates of the tea leaf. The specific activity towards pyrogallol was 373 units/mg. at 30 degrees . 7. The best substrates were o-dihydric phenols. Quinol and p-phenylenediamine were slowly oxidized. Monohydric phenols and ascorbic acid were not oxidized. 8. The kinetics of oxidation of most substrates are consistent with a mechanism in which oxidized and reduced forms of the enzyme form binary complexes with phenol and oxygen respectively. A modified mechanism is postulated for the oxidation of chlorogenic acid. 9. The relation of the results to the mechanism of tea fermentation is discussed.

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TeaCoN: a database of gene co-expression network for tea plant (Camellia sinensis).

Project description:BACKGROUND:Tea plant (Camellia sinensis) is one of the world's most important beverage crops due to its numerous secondary metabolites conferring tea quality and health effects. However, only a small fraction of tea genes (especially for those metabolite-related genes) have been functionally characterized to date. A cohesive bioinformatics platform is thus urgently needed to aid in the functional determination of the remaining genes. DESCRIPTION:TeaCoN, a database of gene co-expression network for tea plant, was established to provide genome-wide associations in gene co-expression to survey gene modules (i.e., co-expressed gene sets) for a function of interest. TeaCoN featured a comprehensive collection of 261 high-quality RNA-Seq experiments that covered a wide range of tea tissues as well as various treatments for tea plant. In the current version of TeaCoN, 31,968 (94% coverage of the genome) tea gene models were documented. Users can retrieve detailed co-expression information for gene(s) of interest in four aspects: 1) co-expressed genes with the corresponding Pearson correlation coefficients (PCC-values) and statistical P-values, 2) gene information (gene ID, description, symbol, alias, chromosomal location, GO and KEGG annotation), 3) expression profile heatmap of co-expressed genes across seven main tea tissues (e.g., leaf, bud, stem, root), and 4) network visualization of co-expressed genes. We also implemented a gene co-expression analysis, BLAST search function, GO and KEGG enrichment analysis, and genome browser to facilitate use of the database. CONCLUSION:The TeaCoN project can serve as a beneficial platform for candidate gene screening and functional exploration of important agronomical traits in tea plant. TeaCoN is freely available at http://teacon.wchoda.com .

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CsTCPs regulate shoot tip development and catechin biosynthesis in tea plant (Camellia sinensis).

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

Transcriptome and metabolite analysis identifies nitrogen utilization genes in tea plant (Camellia sinensis).

Project description:Applied nitrogen (N) fertilizer significantly increases the leaf yield. However, most N is not utilized by the plant, negatively impacting the environment. To date, little is known regarding N utilization genes and mechanisms in the leaf production. To understand this, we investigated transcriptomes using RNA-seq and amino acid levels with N treatment in tea (Camellia sinensis), the most popular beverage crop. We identified 196 and 29 common differentially expressed genes in roots and leaves, respectively, in response to ammonium in two tea varieties. Among those genes, AMT, NRT and AQP for N uptake and GOGAT and GS for N assimilation were the key genes, validated by RT-qPCR, which expressed in a network manner with tissue specificity. Importantly, only AQP and three novel DEGs associated with stress, manganese binding, and gibberellin-regulated transcription factor were common in N responses across all tissues and varieties. A hypothesized gene regulatory network for N was proposed. A strong statistical correlation between key genes' expression and amino acid content was revealed. The key genes and regulatory network improve our understanding of the molecular mechanism of N usage and offer gene targets for plant improvement.

| S-EPMC5431998 | biostudies-literature

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