In the postharvest processing of tea leaves,withering is the first indispensable manufacturing process which produces the mellow,umami and sweet taste of white tea.In this study,we aimed to determine the dynamic chang...In the postharvest processing of tea leaves,withering is the first indispensable manufacturing process which produces the mellow,umami and sweet taste of white tea.In this study,we aimed to determine the dynamic changes of the main metabolites and clarify the key differentially expressed genes(DEGs) involved in forming the characteristic taste of white tea during withering.Phytochemical analyses revealed that the contents of total catechins and starch decreased continuously,whereas the contents of theaflavin,γ-aminobutyric acid(GABA),maltose,and soluble sugars increased significantly during withering(from 0–48 h).Meanwhile,the elevation of α-amylase(AMY),β-amylase(BAM),total amylase,and glutamate decarboxylase(GAD) activities may be correlated with the accumulation of GABA and maltose.By transcriptome sequencing,we detected 9 707,15 921,17 353,and 17 538 DEGs at 12,24,36,and 48 h of the withering process,respectively,compared with 0 h sample(fresh leaves).The transcript levels of most of the DEGs involved in catechin biosynthesis were significantly inhibited,whereas those involved in catechin oxidation were significantly up-regulated,which could be correlated to a decrease in catechin content and an increase in theaflavin content.The DEGs involved in GABA biosynthesis were considerably up-regulated,and the down-regulation of SPMS could reduce the competition for converting spermidine to GABA.The up-regulation of the AMY and BAM genes could trigger starch degradation,resulting in the increase of soluble sugar content.These results provide new insights into the importance of the withering process to the characteristic taste of white tea.展开更多
Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxa...Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxation, and inhibit caffeine’s side effects among others. This current study explored the effects of sunlight and withering durations on theanine levels in tea shoots. Theanine content from three leaves and a bud, two leaves and a bud and internodes were detected and quantified by using High Performance Liquid chromatography (HPLC). Sunlight exposure experiment was started at dawn (0600 HRS, GMT + 3.00) when the light intensity was low and tea was collected at three-hour interval throughout the day to (1800 Hrs, GMT + 3.00) when the light intensity had dropped. At the start of the experiment, the theanine levels were significantly high but as the intensity of sunlight increased during the day there was a significant drop in theanine levels, and as the sun set the theanine levels increased significantly again in all samples. The results also showed that theanine levels were significantly increased after 15 hours of withering. Three leaves and a bud withered for 3 hours had mean theanine levels of 1.41% and those withered for 15 hours had mean theanine levels of 3.11%. Internodes exhibited higher mean theanine levels than those of leaves. In the light of these results, it’s evident that withering for a longer period of time and harvesting of tea when the light intensity is low ensure high amount of theanine in tea.展开更多
At the turn of the century, when big powers are readjusting their relations, ana-lysts are interested in what role the Commonwealth of Independent States(CIS) will play in an unfolding multipolar world in the forthcom...At the turn of the century, when big powers are readjusting their relations, ana-lysts are interested in what role the Commonwealth of Independent States(CIS) will play in an unfolding multipolar world in the forthcoming 21st century.For the moment, however, their attention is focused on the future of the CISitself, an organization committed to integration, yet still plagued with a展开更多
2017 is an election year for Europe,also a year on which hinges the destiny of Europe.In view of the general rise of right-wing populist parties in the EU,there have been concerns if another'black swan'would f...2017 is an election year for Europe,also a year on which hinges the destiny of Europe.In view of the general rise of right-wing populist parties in the EU,there have been concerns if another'black swan'would fly out of the general elections of the Netherland,France and Germany.To date,the Dutch and French展开更多
In the second year of the Shangyuan period(761),Du Fu wrote a quartet of poems on sick or withered trees.They are“The Sick Cypress,”“The Withered Palms,”“The Sick Orange Tree,”and“The Withered Nanmu Tree.”Diff...In the second year of the Shangyuan period(761),Du Fu wrote a quartet of poems on sick or withered trees.They are“The Sick Cypress,”“The Withered Palms,”“The Sick Orange Tree,”and“The Withered Nanmu Tree.”Different from his previous practice of using trees to embody personal aspirations,the poet employed sick or withered trees to allude social realities.These poems,rich with profound contemplation on individuals,society,and the Tang Dynasty,cover many important topics,such as the poet's bleak future,the decline of people's livelihoods,the immorality of rulers,and even the decline of the Tang Dynasty.These poems reveal his disappointment with the future of his country and his personal ambitions.This disenchantment reflects the pivotal shift in Du Fu's later thoughts,revealing the impetus behind his relinquishment of political aspirations in favor of poetic creation.In this regard,this quartet of poems is the most thought-provoking exploration,with an undeniable value among Du Fu's later works.展开更多
Tea flavor is a comprehensive representation of its aroma and other characteristics.The formation of volatile odor compounds during tea processing depends on a variety of enzymatic and non-enzymatic activities.(Z)-3-h...Tea flavor is a comprehensive representation of its aroma and other characteristics.The formation of volatile odor compounds during tea processing depends on a variety of enzymatic and non-enzymatic activities.(Z)-3-hexenol is considered the primary source of the green odor and is also the most important component in tea aroma,significantly affecting the overall aroma.However,the biosynthesis and accumulation of(Z)-3-hexenol during tea processing have not been fully analyzed.In this study,we found that withering treatment at different times and withering plus shaking treatment at different degrees promoted the accumulation of important volatile components of green tea odor,especially(Z)-3-hexenol by GC-MS.The RNA-seq and qRT-PCR results showed that withering and withering plus shaking treatments enhanced the expression of(Z)-3-hexenol-related genes in tea leaves,including synthetic pathway 1 genes(CsLOX3,CsHPL1,CsADH4,and CsAHD1),synthetic pathway 2 genes(CsGLU),and synthetic pathway 3 genes(CsCXEs).Correlation analysis of the key odorants and important genes in the three synthetic pathways revealed that some CsCXEs were positively correlated with green odor compounds.The in vitro enzyme activity results showed that rCsCXE3(GWHTASIV011658),and rCsCXE6(GWHTASIV031480)exhibited hydrolytic activity against three tea acetate compounds[hexyl acetate,(E)-2-hexyl acetate,and(Z)-3-hexyl acetate],resulting in the production of corresponding alcohol compounds.In summary,withering and shaking treatment during tea processing promoted the expression of CsCXE3 and CsCXE6,thereby enhancing the production of hexenol compounds.These compounds play a crucial role in increasing the green odor of tea.展开更多
The epitranscriptomic mark N6-methyladenosine(m^(6)A),which is the predominant internal modification in RNA,is important for plant responses to diverse stresses.Multiple environmental stresses caused by the tea-wither...The epitranscriptomic mark N6-methyladenosine(m^(6)A),which is the predominant internal modification in RNA,is important for plant responses to diverse stresses.Multiple environmental stresses caused by the tea-withering process can greatly influence the accumulation of specialized metabolites and the formation of tea flavor.However,the effects of the m^(6)A-mediated regulatory mechanism on flavor-related metabolic pathways in tea leaves remain relatively uncharacterized.We performed an integrated RNA methylome and transcriptome analysis to explore the m^(6)Amediated regulatory mechanism and its effects on flavonoid and terpenoid metabolism in tea(Camellia sinensis)leaves under solar-withering conditions.Dynamic changes in global m^(6)A level in tea leaves were mainly controlled by two m^(6)A erasers(CsALKBH4A and CsALKBH4B)during solar-withering treatments.Differentially methylated peak-associated genes following solarwithering treatments with different shading rates were assigned to terpenoid biosynthesis and spliceosome pathways.Further analyses indicated that CsALKBH4-driven RNA demethylation can directly affect the accumulation of volatile terpenoids by mediating the stability and abundance of terpenoid biosynthesis-related transcripts and also indirectly influence the flavonoid,catechin,and theaflavin contents by triggering alternative splicing-mediated regulation.Our findings revealed a novel layer of epitranscriptomic gene regulation in tea flavor-related metabolic pathways and established a link between the m^(6)A-mediated regulatory mechanism and the formation of tea flavor under solar-withering conditions.展开更多
基金supported by the China Agriculture Research System of MOF and MARA (CARS-19)the Scientific Research Foundation of Graduate School of Fujian Agriculture and Forestry University, China (102–1122YS010)+6 种基金the Rural Revitalization Tea Industry Technical Service Project of Fujian Agriculture and Forestry University, China (11899170145)the “Double First-class” Scientific and Technological Innovation Capacity and Enhancement Cultivation Plan of Fujian Agriculture and Forestry University, China (KSYLP004)6.18 Tea Industry Technology Branch of Collaborative Innovation Institute, China (K1520001A)the Fujian Agriculture and Forestry University Construction Project for Technological Innovation and Service System of Tea Industry Chain, China (K1520005A01)the Construction of Plateau Discipline of Fujian Province, China (102/71201801101)the Biochemical Analysis and Biological Study of Tea Plant Germplasm Resources of Fujian Agriculture and Forestry University, China (K1518023A)the Innovation Training Program for College Students of Fujian Agriculture and Forestry University, China (102–111ZC20061)。
文摘In the postharvest processing of tea leaves,withering is the first indispensable manufacturing process which produces the mellow,umami and sweet taste of white tea.In this study,we aimed to determine the dynamic changes of the main metabolites and clarify the key differentially expressed genes(DEGs) involved in forming the characteristic taste of white tea during withering.Phytochemical analyses revealed that the contents of total catechins and starch decreased continuously,whereas the contents of theaflavin,γ-aminobutyric acid(GABA),maltose,and soluble sugars increased significantly during withering(from 0–48 h).Meanwhile,the elevation of α-amylase(AMY),β-amylase(BAM),total amylase,and glutamate decarboxylase(GAD) activities may be correlated with the accumulation of GABA and maltose.By transcriptome sequencing,we detected 9 707,15 921,17 353,and 17 538 DEGs at 12,24,36,and 48 h of the withering process,respectively,compared with 0 h sample(fresh leaves).The transcript levels of most of the DEGs involved in catechin biosynthesis were significantly inhibited,whereas those involved in catechin oxidation were significantly up-regulated,which could be correlated to a decrease in catechin content and an increase in theaflavin content.The DEGs involved in GABA biosynthesis were considerably up-regulated,and the down-regulation of SPMS could reduce the competition for converting spermidine to GABA.The up-regulation of the AMY and BAM genes could trigger starch degradation,resulting in the increase of soluble sugar content.These results provide new insights into the importance of the withering process to the characteristic taste of white tea.
文摘Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxation, and inhibit caffeine’s side effects among others. This current study explored the effects of sunlight and withering durations on theanine levels in tea shoots. Theanine content from three leaves and a bud, two leaves and a bud and internodes were detected and quantified by using High Performance Liquid chromatography (HPLC). Sunlight exposure experiment was started at dawn (0600 HRS, GMT + 3.00) when the light intensity was low and tea was collected at three-hour interval throughout the day to (1800 Hrs, GMT + 3.00) when the light intensity had dropped. At the start of the experiment, the theanine levels were significantly high but as the intensity of sunlight increased during the day there was a significant drop in theanine levels, and as the sun set the theanine levels increased significantly again in all samples. The results also showed that theanine levels were significantly increased after 15 hours of withering. Three leaves and a bud withered for 3 hours had mean theanine levels of 1.41% and those withered for 15 hours had mean theanine levels of 3.11%. Internodes exhibited higher mean theanine levels than those of leaves. In the light of these results, it’s evident that withering for a longer period of time and harvesting of tea when the light intensity is low ensure high amount of theanine in tea.
文摘At the turn of the century, when big powers are readjusting their relations, ana-lysts are interested in what role the Commonwealth of Independent States(CIS) will play in an unfolding multipolar world in the forthcoming 21st century.For the moment, however, their attention is focused on the future of the CISitself, an organization committed to integration, yet still plagued with a
文摘2017 is an election year for Europe,also a year on which hinges the destiny of Europe.In view of the general rise of right-wing populist parties in the EU,there have been concerns if another'black swan'would fly out of the general elections of the Netherland,France and Germany.To date,the Dutch and French
文摘In the second year of the Shangyuan period(761),Du Fu wrote a quartet of poems on sick or withered trees.They are“The Sick Cypress,”“The Withered Palms,”“The Sick Orange Tree,”and“The Withered Nanmu Tree.”Different from his previous practice of using trees to embody personal aspirations,the poet employed sick or withered trees to allude social realities.These poems,rich with profound contemplation on individuals,society,and the Tang Dynasty,cover many important topics,such as the poet's bleak future,the decline of people's livelihoods,the immorality of rulers,and even the decline of the Tang Dynasty.These poems reveal his disappointment with the future of his country and his personal ambitions.This disenchantment reflects the pivotal shift in Du Fu's later thoughts,revealing the impetus behind his relinquishment of political aspirations in favor of poetic creation.In this regard,this quartet of poems is the most thought-provoking exploration,with an undeniable value among Du Fu's later works.
基金supported by the Natural Science Foundation of China(Grant Nos.U21A2023 and 32072621)the earmarked fund for CARS-19 and the Youth Science and Technology Talents Support Program(2020)by Anhui Association for Science and Technology(Grant No.RCTJ202010).
文摘Tea flavor is a comprehensive representation of its aroma and other characteristics.The formation of volatile odor compounds during tea processing depends on a variety of enzymatic and non-enzymatic activities.(Z)-3-hexenol is considered the primary source of the green odor and is also the most important component in tea aroma,significantly affecting the overall aroma.However,the biosynthesis and accumulation of(Z)-3-hexenol during tea processing have not been fully analyzed.In this study,we found that withering treatment at different times and withering plus shaking treatment at different degrees promoted the accumulation of important volatile components of green tea odor,especially(Z)-3-hexenol by GC-MS.The RNA-seq and qRT-PCR results showed that withering and withering plus shaking treatments enhanced the expression of(Z)-3-hexenol-related genes in tea leaves,including synthetic pathway 1 genes(CsLOX3,CsHPL1,CsADH4,and CsAHD1),synthetic pathway 2 genes(CsGLU),and synthetic pathway 3 genes(CsCXEs).Correlation analysis of the key odorants and important genes in the three synthetic pathways revealed that some CsCXEs were positively correlated with green odor compounds.The in vitro enzyme activity results showed that rCsCXE3(GWHTASIV011658),and rCsCXE6(GWHTASIV031480)exhibited hydrolytic activity against three tea acetate compounds[hexyl acetate,(E)-2-hexyl acetate,and(Z)-3-hexyl acetate],resulting in the production of corresponding alcohol compounds.In summary,withering and shaking treatment during tea processing promoted the expression of CsCXE3 and CsCXE6,thereby enhancing the production of hexenol compounds.These compounds play a crucial role in increasing the green odor of tea.
基金supported by the Earmarked Fund for China Agriculture Research System of Ministry of Finance and Ministry of Agriculture and Rural Affairs(Grant No.CARS-19)the Scientific Research Foundation of Graduate School of Fujian Agriculture and Forestry University(Grant No.324-1122yb070)+7 种基金the Scientific Research Foundation of Horticulture College of Fujian Agriculture and Forestry University(Grant No.2019B01)the Rural Revitalization Tea Industry Technical Service Project of Fujian Agriculture and Forestry University(Grant No.11899170145)the“Double first-class”scientific and technological innovation capacity and enhancement cultivation plan of Fujian Agriculture and Forestry University(Grant No.KSYLP004)the 6.18 Tea Industry Technology Branch of Collaborative Innovation Institute(Grant No.K1520001A)the Fujian Agriculture and Forestry University Construction Project for Technological Innovation and Service System of Tea Industry Chain(Grant No.K1520005A01)the Construction of Plateau Discipline of Fujian Province(Grant No.102/71201801101)the Tea Industry Branch of Collaborative Innovation Institute of Fujian Agriculture and Forestry University(Grant No.K1521015A)the Special Fund for Science and Technology Innovation of Fujian Zhang Tianfu Tea Development Foundation(Grant No.FJZTF01),China.
文摘The epitranscriptomic mark N6-methyladenosine(m^(6)A),which is the predominant internal modification in RNA,is important for plant responses to diverse stresses.Multiple environmental stresses caused by the tea-withering process can greatly influence the accumulation of specialized metabolites and the formation of tea flavor.However,the effects of the m^(6)A-mediated regulatory mechanism on flavor-related metabolic pathways in tea leaves remain relatively uncharacterized.We performed an integrated RNA methylome and transcriptome analysis to explore the m^(6)Amediated regulatory mechanism and its effects on flavonoid and terpenoid metabolism in tea(Camellia sinensis)leaves under solar-withering conditions.Dynamic changes in global m^(6)A level in tea leaves were mainly controlled by two m^(6)A erasers(CsALKBH4A and CsALKBH4B)during solar-withering treatments.Differentially methylated peak-associated genes following solarwithering treatments with different shading rates were assigned to terpenoid biosynthesis and spliceosome pathways.Further analyses indicated that CsALKBH4-driven RNA demethylation can directly affect the accumulation of volatile terpenoids by mediating the stability and abundance of terpenoid biosynthesis-related transcripts and also indirectly influence the flavonoid,catechin,and theaflavin contents by triggering alternative splicing-mediated regulation.Our findings revealed a novel layer of epitranscriptomic gene regulation in tea flavor-related metabolic pathways and established a link between the m^(6)A-mediated regulatory mechanism and the formation of tea flavor under solar-withering conditions.
