Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the ...repeat-rich （80.9%）, 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.
Microbial enzymes during solid-state fermentation (SSF), which play important roles in the food, chemical, pharmaceutical and environmental fields, remain relatively unknown. In this work, the ...microbial communities and enzymes in SSF of Pu-erh tea, a well-known traditional Chinese tea, were investigated by integrated metagenomics/metaproteomics approach. The dominant bacteria and fungi were identified as Proteobacteria (48.42%) and Aspergillus (94.98%), through pyrosequencing-based analyses of the bacterial 16S and fungal 18S rRNA genes, respectively. In total, 335 proteins with at least two unique peptides were identified and classified into 28 Biological Processes and 35 Molecular Function categories using a metaproteomics analysis. The integration of metagenomics and metaproteomics data demonstrated that Aspergillus was dominant fungus and major host of identified proteins (50.45%). Enzymes involved in the degradation of the plant cell wall were identified and associated with the soft-rotting of tea leaves. Peroxiredoxins, catalase and peroxidases were associated with the oxidation of catechins. In conclusion, this work greatly advances our understanding of the SSF of Pu-erh tea and provides a powerful tool for studying SSF mechanisms, especially in relation to the microbial communities present.
Although China and India are the two largest tea-producing countries, the domestication origin and breeding history of the tea plant in these two countries remain unclear. Our previous study ...suggested that the tea plant includes three distinct lineages (China type tea, Chinese Assam type tea and Indian Assam type tea), which were independently domesticated in China and India, respectively. To determine the origin and historical timeline of tea domestication in these two countries we used a combination of 23 nSSRs (402 samples) and three cpDNA regions (101 samples) to genotype domesticated tea plants and its wild relative. Based on a combination of demographic modeling, NewHybrids and Neighbour joining tree analyses, three independent domestication centers were found. In addition, two origins of Chinese Assam type tea were detected: Southern and Western Yunnan of China. Results from demographic modeling suggested that China type tea and Assam type tea first diverged 22,000 year ago during the last glacial maximum and subsequently split into the Chinese Assam type tea and Indian Assam type tea lineages 2770 year ago, corresponding well with the early record of tea usage in Yunnan, China. Furthermore, we found that the three tea types underwent different breeding histories where hybridization appears to have been the most important approach for tea cultivar breeding and improvements: a high proportion of the hybrid lineages were found to be F
and BCs. Collectively, our results underscore the necessity for the conservation of Chinese Assam type tea germplasm and landraces as a valuable resource for future tea breeding.
Leaves are one of the most important organs of plants, and yet, the association between leaf color and consumable traits remains largely unclear. Tea leaves are an ideal study system with which to ...investigate the mechanism of how leaf coloration affects palatability, since tea is made from the leaves of the crop
. Our genomic resequencing analysis of a tea cultivar ZiJuan (ZJ) with purple leaves and altered flavor revealed genetic variants when compared with the green-leaf, wild type cultivar YunKang(YK). RNA-Seq based transcriptomic comparisons of the bud and two youngest leaves in ZJ and YK identified 93%, 9% and 5% expressed genes that were shared in YK- and ZJ-specific cultivars, respectively. A comparison of both transcript abundance and particular metabolites revealed that the high expression of gene
for anthocyanin biosynthesis is responsible for purple coloration, which competes with the intermediates for catechin-like flavanol biosynthesis. Genes with differential expression are enriched in response to stress, heat and defense, and are casually correlated with the environmental stress of ZJ plant origin in the Himalayas. In addition, the highly expressed
and
genes for synthesizing flavanol precursors, ZJ-specific
for degrading chlorophyll, alternatively spliced
and
and low photosynthesis also contributed to the altered color and flavor of ZJ. Thus, our study provides a better molecular understanding of the effect of purple coloration on leaf flavor, and helps to guide future engineering improvement of palatability.
Camellia taliensis is one of the most important wild relatives of cultivated tea tree, C. sinensis. The species extensively occupies mountainous habitats representing a wide-range abiotic tolerance ...and biotic resistance and thus harbors valuable gene resources that may greatly benefit genetic improvement of cultivated tea tree. However, owning to a large genome size of ~3 Gb and structurally complex genome, there are fairly limited genetic information and particularly few genomic resources publicly available for this species. To better understand the key pathways determining tea flavor and enhance tea tree breeding programs, we performed a high-throughput transcriptome sequencing for C. taliensis.
In this study, approximate 241.5 million high-quality paired-end reads, accounting for ~24 Gb of sequence data, were generated from tender shoots, young leaves, flower buds and flowers using Illumina HiSeq 2000 platform. De novo assembly with further processing and filtering yielded a set of 67,923 transcripts with an average length of 685 bp and an N50 of 995 bp. Based on sequence similarity searches against public databases, a total of 39,475 transcripts were annotated with gene descriptions, conserved protein domains or gene ontology (GO) terms. Candidate genes for major metabolic pathways involved in tea quality were identified and experimentally validated using RT-qPCR. Further gene expression profiles showed that they are differentially regulated at different developmental stages. To gain insights into the evolution of these genes, we aligned them to the previously cloned orthologous genes in C. sinensis, and found that considerable nucleotide variation within several genes involved in important secondary metabolic biosynthesis pathways, of which flavone synthase II gene (FNSII) is the most variable between these two species. Moreover, comparative analyses revealed that C. taliensis shows a remarkable expansion of LEA genes, compared to C. sinensis, which might contribute to the observed stronger stress resistance of C. taliensis.
We reported the first large-coverage transcriptome datasets for C. taliensis using the next-generation sequencing technology. Such comprehensive EST datasets provide an unprecedented opportunity for identifying genes involved in several major metabolic pathways and will accelerate functional genomic studies and genetic improvement efforts of tea trees in the future.
A field experiment was conducted in 2012, including three planting pattern (maize-soybean relay strip intercropping, mono-cultured maize and soybean) and three nitrogen application level 0 kg N x ...hm(-2), 180 kg N x hm(-2) (reduced N) and 240 kg N x hm(-2) (normal N). Fields were assigned to different treatments in a randomized block design with three replicates. The objective of this work was to analyze the effects of planting patterns and nitrogen application rates on plant N uptake, soil N residue and N loss. After fertilization applications, NH4(+)-N and NO3(-)-N levels increased in the soil of intercropped maize but decreased in the soil of intercropped soybean. Compared with mono-crops, the soil N residue and loss of intercropped soybean were reduced, while those of intercropped maize were increased and decreased, respectively. With the reduced rate of N application, N residue rate, N loss rate and ammonia volatilization loss rate of the maize-soybean intercropping relay strip system were decreased by
A field experiment with three N application rates (0, 180, 240 N kg x hm(-2), representing zero, reduced and conventional N application, respectively) and three planting patterns (maize monoculture, ...soybean monoculture and maize-soybean relay strip intercropping) was conducted to reveal the effects of cropping patterns and N application rates on yield, nutrient uptake and nitrogen use efficiency of maize and soybean. The results showed that the grain yield, N, P and K uptake and harvest index of the intercropped maize reduced slightly compared with the monoculture maize, however these indices of the intercropped soybean increased significantly compared with the monoculture. With the increase in nitrogen fertilizer application, the excellence of relay strip intercropping was weakened in the maize-soybean intercropping system. The grain yield, economic coefficient, N, P and K uptake, harvest index, N agronomy efficiency and N uptake efficiency of maize and soybean increased significantly at the reduced nitrogen
A surfactant containing a mixed aliphatic structure, with a hydrocarbon chain and a diamine group, has proven to be collector for the flotation of quartz, calamine and calcite. And research about its ...collecting capability was carried out in laboratory. The test results show that the flotation recovery ascends sharply with increasing the concentration of collector. When the concentration of collector reaches 1.83×10
−4 mol/L, the flotation recoveries of quartz, calamine and calcite get their maximum of 97.64%, 91.04% and 95.99%, respectively. The flotation recoveries of quartz, calamine and calcite rise sharply with the rise of pH. And in a wide range of pH, their flotation recoveries all exceed 90%. And in the whole flotation experiment, the flotation recovery of hematite rises with the increase of collector concentration and pH, while the maximal recovery is not more than 55%. Compared with dodecylamine, the
N-dodecylethylenediamine has strong capability to quartz and calamine, while the flotation recoveries of calcite are closely. Hydrogen binding adsorption and electrostatic adsorption occur between the collector and the surface of quartz.
AIM:To determine the effect of apoptosis on gastric cancer cells(SGC-7901)induced by cis-9,trans-11-conjugated linoleic acid(c9,t11-CLA)and its possible mechanism in the inhibition of cancer cells ...growth.
To explore the inhibition of conjugated linoleic acid isomers in different purity (75 % purity c9,t11-, 98 % purity c9,t11- and 98 % purity t10,c12-CLA) on the formation of forestomach neoplasm and ...chemopreventive mechanisms.
Forestomach neoplasm model induced by B(a)P in KunMing mice was established. The numbers of tumor and diameter of each tumor in forestomach were counted; the mice plasma malondialdehyde (MDA) were measured by TBARS assay; TUNEL assay was used to analyze the apoptosis in forestomach neoplasia and the expression of MEK-1, ERK-1, MKP-1 protein in forestomach neoplasm were studied by Western Blotting assay.
The incidence of neoplasm in B(a)P group, 75 % purity c9, t11-CLA group, 98 % purity c9,t11-CLA group and 98 % purity t10, c12-CLA group was 100 %, 75.0 %(P>0.05), 69.2 % (P<0.05) and 53.8 % (P<0.05) respectively and the effect of two CLA isomers in 98 % purity on forestomach neoplasia was significant; CLA showed no influence on the average tumor numbers in tumor-bearing mouse, but significantly decreased the tumor size, the tumor average diameter of mice in 75 % purity c9,t11-CLA group, 98 % purity c9,t11-CLA group and 98 % purity t10, c12-CLA group was 0.157+/-0.047 cm, 0.127+/-0.038 cm and 0.128+/-0.077 cm (P<0.05) and 0.216+/-0.088 cm in B(a)P group; CLA could also significantly increase the apoptosis cell numbers by 144.00+/-20.31, 153.75+/-23.25, 157.25+/-15.95(P<0.05) in 75 % purity c9,t11-CLA group, 98 % purity c9,t11-CLA group and 98 % purity t10,c12-CLA group (30.88+/-3.72 in BP group); but there were no significant differences between the effects of 75 % purity c9,t11-CLA and two isomers in 98 % purity on tumor size and apoptotic cell numbers; the plasma levels of MDA in were increased by 75 % purity c9,t11-CLA, 98 % purity c9,t11-CLA and 98 % purity t10,c12-CLA. The 75 % purity c9,t11-CLA showed stronger inhibition; CLA could also inhibit the expression of ERK-1 protein and promote the expression of MKP-1 protein, however no influence of CLA on MEK-1 protein was observed.
Two isomers in 98 % purity show stronger inhibition on carcinogenesis. However, the inhibitory mechanisms of CLA on carcinogenesis is complicated, which may be due to the increased mice plasma MDA, the inducing apoptosis in tumor tissues. And the effect of CLA on the expression of ERK-1 and MKP-1 may be one of the mechanisms of the inhibition of CLA on the tumor.
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