Metabolic analyses reveal different mechanisms of leaf color change in two purple-leaf tea plant (Camellia sinensis L.) cultivars

Purple-leaf tea plants,as anthocyanin-rich cultivars,are valuable materials for manufacturing teas with unique colors or flavors.In this study,a new purple-leaf cultivar“Zixin”(“ZX”)was examined,and its biochemical variation and mechanism of leaf color change were elucidated.The metabolomes of leaves of“ZX”at completely purple,intermediately purple,and completely green stages were analyzed using ultra-performance liquid chromatography quadrupole time of flight mass spectrometry(UPLC-QTOF-MS).Metabolites in the flavonoid biosynthetic pathway remained at high levels in purple leaves,whereas intermediates of porphyrin and chlorophyll metabolism and carotenoid biosynthesis exhibited high levels in green leaves.In addition,fatty acid metabolism was more active in purple leaves,and steroids maintained higher levels in green leaves.Saponin,alcohol,organic acid,and terpenoid-related metabolites also changed significantly during the leaf color change process.Furthermore,the substance changes between“ZX”and“Zijuan”(a thoroughly studied purple-leaf cultivar)were also compared.The leaf color change in“Zijuan”was mainly caused by a decrease in flavonoids/anthocyanins.However,a decrease in flavonoids/anthocyanins,an enhancement of porphyrin,chlorophyll metabolism,carotenoid biosynthesis,and steroids,and a decrease in fatty acids synergistically caused the leaf color change in“ZX”.These findings will facilitate comprehensive research on the regulatory mechanisms of leaf color change in purple-leaf tea cultivars.

Transcriptomic analyses identify albino-associated genes of a novel albino tea germplasm ‘Huabai 1’

Albinism in shoots of tea plants is a common phenotypic expression which gives the tea infusion a pleasant umami taste.A novel natural albino mutant tea germplasm containing high amino acids content was found and named as‘Huabai 1’.‘Huabai 1’has white jade tender shoots under low temperature and turns green with increased temperature.In order to understand the molecular mechanism of color change in leaf of‘Huabai 1’,transcriptome analysis was performed to identify albino-associated differentially expressed genes(DEGs).A total of 483 DEGs were identified from white shoots of‘Huabai 1’compared to its green shoots.There were 15 DEGs identified to be involved in phenylpropanoid biosynthesis,which account for the majority of characterized DEGs.The metabolites related to phenylpropanoid biosynthesis revealed similar expression pattern of DEGs.Furthermore,metabolic pathways such as ubiquonone,tyrosine,and flavonoid biosynthesis associated with phenylpropanoid biosynthesis could also contribute to the color change in‘Huabai 1’tender shoots.Protein–protein interaction analysis revealed a hub protein NEDD8(CSA009575)which interacted with many regulated genes in spliceosome,nitrogen metabolism,phenylpropanoid biosynthesis,and other pathways.In conclusion,the findings in this study indicate that the color change of‘Huabai 1’tender shoots is a combined effect of phenylpropanoid biosynthesis pathway and other metabolic pathways including flavonoid biosynthesis in tea plants.Chlorophyll biosynthesis-related genes LHCII and SGR may also play some roles in color change of‘Huabai 1’.

TeaPGDB:Tea Plant Genome Database

As the most widely consumed beverage in the world,tea has various nutritional,economic,and global cultural values.With the development of the third-generation sequencing technology,several genome sequences of tea plants have been published.These genomic data have pivotal information that is of benefit to tea plant breeders and biologists in advancing tea plant improvement and the final quality of tea products.We hereby present the integrative online database,Tea Plant Genome Database(TeaPGDB;http://eplant.njau.edu.cn/tea),which incorporates the published genome sequences of tea plants.The current release of TeaPGDB hosts published tea plant genome data with various online tools,including JBrowse,gene search,SSR search,BLAST.TeaPGDB also contains a download server,which provides access for the download of genome-related data and rich annotation files.TeaPGDB is committed to collecting,integrating,and annotating published tea plant genome data,providing data support for research on tea plant heredity,evolution,breeding for resistance,plant improvement,and facilitating the characterization of important traits or flavor related genes in the community.Compared with other tea plant databases,this database not only contains more complete genome data and gene annotation information,but also has a user-friendly interface for researchers in the field.

Progress and perspective on intercropping patterns in tea plantations

Intercropping,as one of the complex ecological cultivations,is an important tea plantation pattern.Compared to sole-cropping tea plantations,intercropping can improve the above-and below-ground environment,which is beneficial to tea plant growth,the formation of high tea quality and the increase of tea yield.In this review,we summarized the impacts of intercropping on the tea plantation environment(microclimate,biomass,soil nutrients,microorganisms and heavy metals),tea plants growth and tea yield.We then analyzed how intercropping affects the growth and metabolism of tea plants based on the impact of intercropping on the environment.As a result,the achievements and progress of tea plantation intercropping are summarized,the remaining problems of the current research on intercropping tea plantations are highlighted,and provide new insights for the advanced research of intercropping in tea plantations.

Targeted metabolomics reveals dynamic changes during the manufacturing process of Yuhua tea,a stir-fried green tea

The chemical composition of Yuhua tea is in a state of constant change during tea processing.However,the dynamic changes in this complex metabolic process remain unclear.Therefore,we detected the changes of compounds in the five stages of processing of Yuhua tea,and carried out metabolomic analysis based on UPLC–MS.In total,898 metabolites were detected in the five different stages.In the spreading and fixation processes,the differences in metabolites were the most significant,with 127 and 150 metabolites,respectively,undergoing significant changes.During the spreading period,the levels of amino acids and their derivatives,as well as flavonoids,increased sharply,and most continued to increase or stabilized after spreading.In addition,only 26 and 95 metabolites changed significantly during the rolling and drying processes,respectively.Orthogonal projections to latent structures-discriminant analysis showed that the metabolomics of tea changed significantly during the manufacturing process,especially amino acids and derivatives,flavonoids and lipids.This study provides a comprehensive overview of the metabolic changes during the processing of stir-fried green tea,which has potential significance for quality control and flavor improvement of tea.