The carotenoid-derived volatileβ-ionone makes an important contribution to tea fragrance.Here,we qualitatively and quantitatively analysed 15 carotenoids in tea leaves of 13 cultivars by UHPLC-APCI-MS/MS.The 13 culti...The carotenoid-derived volatileβ-ionone makes an important contribution to tea fragrance.Here,we qualitatively and quantitatively analysed 15 carotenoids in tea leaves of 13 cultivars by UHPLC-APCI-MS/MS.The 13 cultivars were divided into two groups by PCA(Principal Component Analysis)clustering analysis of their carotenoid content,and OPLS-DA(Orthogonal projections to latent structures)indicated that the levels ofβ-carotene(VIP=2.89)and lutein(VIP=2.30)were responsible for much of the variation between the two groups.Interestingly,theβ-carotene toβ-ionone conversion rates in Group 1 were higher than in Group 2,while theβ-carotene content was significantly lower in Group 1 than in Group 2.Theβ-ionone content was significantly higher in Group 1.Pearson Correlation Coefficient calculation between the transcription level of candidate genes(CsCCD1 and CsCCD4)and the accumulation ofβ-ionone indicated that CsCCD1 may involve in the formation ofβ-ionone in 13 cultivars.Prokaryotic expression and in vitro enzyme activity assays showed that‘Chuanhuang 1’had an amino acid mutation in carotenoid cleavage dioxygenases 1(CsCCD1)compared with‘Shuchazao’,resulting in a significantly higherβ-ionone content in‘Chuanhuang 1’.Sequence analysis showed that‘Chuanhuang 1’and‘Huangdan’had different CsCCD1 promoter sequences,leading to significantly higher CsCCD1 expression andβ-ionone accumulation in‘Chuanhuang 1’.These results indicated that the promoter and coding sequence diversity of CsCCD1 might contribute to the differential accumulation ofβ-ionone in different tea cultivars.展开更多
4-Hydroxy-2,5-dimethylfuran-3(2H)-one(HDMF)is an important odorant in some fruits,and is proposed to play a crucial role in the caramel-like notes of some teas.However,its biosynthesis and metabolism in tea plants are...4-Hydroxy-2,5-dimethylfuran-3(2H)-one(HDMF)is an important odorant in some fruits,and is proposed to play a crucial role in the caramel-like notes of some teas.However,its biosynthesis and metabolism in tea plants are still unknown.Here,HDMF glucoside was unambiguously identified as a native metabolite in tea plants.A novel glucosyltransferase UGT74AF3a and its allelic protein UGT74AF3b specifically catalyzed the glucosylation of HDMF and the commercially important structural homologues 2(or 5)-ethyl-4-hydroxy-5(or 2)-methylfuran-3(2H)-one(EHMF)and 4-hydroxy-5-methylfuran-3(2H)-one(HMF)to their correspondingβ-D-glucosides.Site-directed mutagenesis of UGT74AF3b to introduce a single A456V mutation resulted in improved HDMF and EHMF glucosylation activity and affected the sugar donor preference compared with that of the wild-type control enzyme.The accumulation of HDMF glucoside was consistent with the transcript levels of UGT74AF3 in different tea cultivars.In addition,transient UGT74AF3a overexpression in tobacco significantly increased the HDMF glucoside contents,and downregulation of UGT74AF3 transcripts in tea leaves significantly reduced the concentration of HDMF glucoside compared with the levels in the controls.The identification of HDMF glucoside in the tea plant and the discovery of a novel-specific UDP-glucose:HDMF glucosyltransferase in tea plants provide the foundation for improvement of tea flavor and the biotechnological production of HDMF glucoside.展开更多
Lipoxygenase(LOX)is an important contributor to the formation of aroma-active C6 aldehydes in apple(Malus×domestica)fruit upon tissue disruption but little is known about its role in autonomously produced aroma v...Lipoxygenase(LOX)is an important contributor to the formation of aroma-active C6 aldehydes in apple(Malus×domestica)fruit upon tissue disruption but little is known about its role in autonomously produced aroma volatiles from intact tissue.We explored the expression of 22 putative LOX genes in apple throughout ripening,but only six LOXs were expressed in a ripening-dependent manner.Recombinant LOX1:Md:1a,LOX1:Md:1c,LOX2:Md:2a and LOX2:Md:2b proteins showed 13/9-LOX,9-LOX,13/9-LOX and 13-LOX activity with linoleic acid,respectively.While products of LOX1:Md:1c and LOX2:Md:2b were S-configured,LOX1:Md:1a and LOX2:Md:2a formed 13(R)-hydroperoxides as major products.Site-directed mutagenesis of Gly567 to an alanine converted the dual positional specific LOX1:Md:1a to an enzyme with a high specificity for 9(S)-hydroperoxide formation.The high expression level of the corresponding MdLOX1a gene in stored apple fruit,the genetic association with a quantitative trait locus for fruit ester and the remarkable agreement in regio-and stereoselectivity of the LOX1:Md:1a reaction with the overall LOX activity found in mature apple fruits,suggest a major physiological function of LOX1:Md:1a during climacteric ripening of apples.While LOX1:Md:1c,LOX2:Md:2a and LOX2:Md:2b may contribute to aldehyde production in immature fruit upon cell disruption our results furnish additional evidence that LOX1:Md:1a probably regulates the availability of precursors for ester production in intact fruit tissue.展开更多
Plants have developed sophisticated mechanisms to survive in dynamic environments.Plants can communicate via volatile organic compounds(VOCs)to warn neighboring plants of threats.In most cases,VOCs act as positive reg...Plants have developed sophisticated mechanisms to survive in dynamic environments.Plants can communicate via volatile organic compounds(VOCs)to warn neighboring plants of threats.In most cases,VOCs act as positive regulators of plant defense.However,the communication and role of volatiles in response to drought stress are poorly understood.Here,we showed that tea plants release numerous VOCs.Among them,methyl salicylate(MeSA),benzyl alcohol,and phenethyl alcohol markedly increased under drought stress.Interestingly,further experiments revealed that drought-induced MeSA lowered the abscisic acid(ABA)content in neighboring plants by reducing 9-cis-epoxycarotenoid dioxygenase(NCED)gene expression,resulting in inhibition of stomatal closure and ultimately decreasing early drought tolerance in neighboring plants.Exogenous application of ABA reduced the wilting of tea plants caused by MeSA exposure.Exposure of Nicotiana benthamiana to MeSA also led to severe wilting,indicating that the ability of drought-induced MeSA to reduce early drought tolerance in neighboring plants may be conserved in other plant species.Taken together,these results provide evidence that drought-induced volatiles can reduce early drought tolerance in neighboring plants and lay a novel theoretical foundation for optimizing plant density and spacing.展开更多
The strawberry Fra a 1 proteins belong to the class 10 Pathogenesis-Related(PR-10)superfamily.In strawberry,a large number of members have been identified,but only a limited number is expressed in the fruits.In this o...The strawberry Fra a 1 proteins belong to the class 10 Pathogenesis-Related(PR-10)superfamily.In strawberry,a large number of members have been identified,but only a limited number is expressed in the fruits.In this organ,Fra a 1.01 and Fra a 1.02 are the most abundant Fra proteins in the green and red fruits,respectively,however,their function remains unknown.To know the function of Fra a 1.02 we have generated transgenic lines that silence this gene,and performed metabolomics,RNA-Seq,and hormonal assays.Previous studies associated Fra a 1.02 to strawberry fruit color,but the analysis of anthocyanins in the ripe fruits showed no diminution in their content in the silenced lines.Gene ontology(GO)analysis of the genes differentially expressed indicated that oxidation/reduction was the most represented biological process.Redox state was not apparently altered since no changes were found in ascorbic acid and glutathione(GSH)reduced/oxidized ratio,but GSH content was reduced in the silenced fruits.In addition,a number of glutathione-S-transferases(GST)were down-regulated as result of Fra a 1.02-silencing.Another highly represented GO category was transport which included a number of ABC and MATE transporters.Among the regulatory genes differentially expressed WRKY33.1 and WRKY33.2 were down-regulated,which had previously been assigned a role in strawberry plant defense.A reduced expression of the VQ23 gene and a diminished content of the hormones JA,SA,and IAA were also found.These data might indicate that Fra a 1.02 participates in the defense against pathogens in the ripe strawberry fruits.展开更多
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 ...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.展开更多
Geraniol is an important contributor to the pleasant floral scent of tea products and one of the most abundant aroma compounds in tea plants;however,its biosynthesis and physiological function in response to stress in...Geraniol is an important contributor to the pleasant floral scent of tea products and one of the most abundant aroma compounds in tea plants;however,its biosynthesis and physiological function in response to stress in tea plants remain unclear.The proteins encoded by the full-length terpene synthase(CsTPS1)and its alternative splicing isoform(CsTPS1-AS)could catalyze the formation of geraniol when GPP was used as a substrate in vitro,whereas the expression of CsTPS1-AS was only significantly induced by Colletotrichum gloeosporioides and Neopestalotiopsis sp.infection.Silencing of CsTPS1 and CsTPS1-AS resulted in a significant decrease of geraniol content in tea plants.The geraniol content and disease resistance of tea plants were compared when CsTPS1 and CsTPS1-AS were silenced.Down-regulation of the expression of CsTPS1-AS reduced the accumulation of geraniol,and the silenced tea plants exhibited greater susceptibility to pathogen infection than control plants.However,there was no significant difference observed in the geraniol content and pathogen resistance between CsTPS1-silenced plants and control plants in the tea plants infected with two pathogens.Further analysis showed that silencing of CsTPS1-AS led to a decrease in the expression of the defense-related genes PR1 and PR2 and SA pathway-related genes in tea plants,which increased the susceptibility of tea plants to pathogens infections.Both in vitro and in vivo results indicated that CsTPS1 is involved in the regulation of geraniol formation and plant defense via alternative splicing in tea plants.The results of this study provide new insights into geraniol biosynthesis and highlight the role of monoterpene synthases in modulating plant disease resistance via alternative splicing.展开更多
Strawberry(Fragaria×ananassa)fruits are an excellent source of L-ascorbic acid(AsA),a powerful antioxidant for plants and humans.Identifying the genetic components underlying AsA accumulation is crucial for enhan...Strawberry(Fragaria×ananassa)fruits are an excellent source of L-ascorbic acid(AsA),a powerful antioxidant for plants and humans.Identifying the genetic components underlying AsA accumulation is crucial for enhancing strawberry nutritional quality.Here,we unravel the genetic architecture of AsA accumulation using an F1 population derived from parental lines‘Candonga’and‘Senga Sengana’,adapted to distinct Southern and Northern European areas.To account for environmental effects,the F1 and parental lines were grown and phenotyped in five locations across Europe(France,Germany,Italy,Poland and Spain).Fruit AsA content displayed normal distribution typical of quantitative traits and ranged five-fold,with significant differences among genotypes and environments.AsA content in each country and the average in all of them was used in combination with 6,974 markers for quantitative trait locus(QTL)analysis.Environmentally stable QTLs for AsA content were detected in linkage group(LG)3A,LG 5A,LG 5B,LG 6B and LG 7C.Candidate genes were identified within stable QTL intervals and expression analysis in lines with contrasting AsA content suggested that GDP-L-Galactose Phosphorylase FaGGP(3A),and the chloroplast-located AsA transporter gene FaPHT4;4(7C)might be the underlying genetic factors for QTLs on LG 3A and 7C,respectively.We show that recessive alleles of FaGGP(3A)inherited from both parental lines increase fruit AsA content.Furthermore,expression of FaGGP(3A)was two-fold higher in lines with high AsA.Markers here identified represent a useful resource for efficient selection of new strawberry cultivars with increased AsA content.展开更多
Plants respond to environmental stimuli via the release of volatile organic compounds(VOCs),and neighboring plants constantly monitor and respond to these VOCs with great sensitivity and discrimination.This sensing ca...Plants respond to environmental stimuli via the release of volatile organic compounds(VOCs),and neighboring plants constantly monitor and respond to these VOCs with great sensitivity and discrimination.This sensing can trigger increased plant fitness and reduce future plant damage through the priming of their own defenses.The defense mechanism in neighboring plants can either be induced by activation of the regulatory or transcriptional machinery,or it can be delayed by the absorption and storage of VOCs for the generation of an appropriate response later.Despite much research,many key questions remain on the role of VOCs in interplant communication and plant fitness.Here we review recent research on the VOCs induced by biotic(i.e.insects and pathogens)and abiotic(i.e.cold,drought,and salt)stresses,and elucidate the biosynthesis of stress-induced VOCs in tea plants.Our focus is on the role of stress-induced VOCs in complex ecological environments.Particularly,the roles of VOCs under abiotic stress are highlighted.Finally,we discuss pertinent questions and future research directions for advancing our understanding of plant interactions via VOCs.展开更多
Uridine diphosphate-dependent glycosyltransferases(UGTs)mediate the glycosylation of plant metabolites,thereby altering their physicochemical properties and bioactivities.Plants possess numerous UGT genes,with the enc...Uridine diphosphate-dependent glycosyltransferases(UGTs)mediate the glycosylation of plant metabolites,thereby altering their physicochemical properties and bioactivities.Plants possess numerous UGT genes,with the encoded enzymes often glycosylating multiple substrates and some exhibiting substrate inhibition kinetics,but the biological function and molecular basis of these phenomena are not fully understood.The promiscuous monolignol/phytoalexin glycosyltransferase NbUGT72AY1 exhibits substrate inhibition(Ki)at 4 mM scopoletin,whereas the highly homologous monolignol StUGT72AY2 is inhibited at 190 mM.We therefore used hydrogen/deuterium exchange mass spectrometry and structure-based mutational analyses of both proteins and introduced NbUGT72AY1 residues into StUGT72AY2 and vice versa to study promiscuity and substrate inhibition of UGTs.A single F87I and chimeric mutant of NbUGT72AY1 showed significantly reducedscopoletin substrate inhibition,whereas its monolignolgly cosylation activity was almost unaffected.Reverse mutations in StUGT72AY2 resulted in increased scopoletin glycosylation,leading to enhanced promiscuity,which was accompanied by substrate inhibition.Studies of 3D structures identified open and closed UGT conformers,allowing visualization of the dynamics of conformational changes that occur during catalysis.Previously postulated substrate access tunnels likely serve as drainage channels.The results suggest a two-site model in which the second substrate molecule binds near the catalytic site and blocks product release.Mutational studies showed that minor changes in amino acid sequence can enhance the promiscuity of the enzyme and add new capabilities such as substrate inhibition without affecting existing functions.The proposed subfunctionalization mechanism of expanded promiscuity may play a role in enzyme evolution and highlights the importance of promiscuous enzymes in providing new functions.展开更多
Plants have evolved sophisticated defense mechanisms to overcome their sessile nature.However,if and how volatiles from cold‐stressed plants can trigger interplant communication is still unknown.Here,we provide the f...Plants have evolved sophisticated defense mechanisms to overcome their sessile nature.However,if and how volatiles from cold‐stressed plants can trigger interplant communication is still unknown.Here,we provide the first evidence for interplant communication via inducible volatiles in cold stress.The volatiles,including nerolidol,geraniol,linalool,and methyl salicylate,emitted from cold‐stressed tea plants play key role(s)in priming cold tolerance of their neighbors via a C‐repeatbinding factors‐dependent pathway.The knowledge will help us to understand how plants respond to volatile cues in cold stress and agricultural ecosystems.展开更多
基金financially supported by National Natural Science Foundation of China(Grant Nos.31961133030,31870678,32022076)Science Fund for Distinguished Young Scientists of Anhui Province(Grant No.1908085J12).
文摘The carotenoid-derived volatileβ-ionone makes an important contribution to tea fragrance.Here,we qualitatively and quantitatively analysed 15 carotenoids in tea leaves of 13 cultivars by UHPLC-APCI-MS/MS.The 13 cultivars were divided into two groups by PCA(Principal Component Analysis)clustering analysis of their carotenoid content,and OPLS-DA(Orthogonal projections to latent structures)indicated that the levels ofβ-carotene(VIP=2.89)and lutein(VIP=2.30)were responsible for much of the variation between the two groups.Interestingly,theβ-carotene toβ-ionone conversion rates in Group 1 were higher than in Group 2,while theβ-carotene content was significantly lower in Group 1 than in Group 2.Theβ-ionone content was significantly higher in Group 1.Pearson Correlation Coefficient calculation between the transcription level of candidate genes(CsCCD1 and CsCCD4)and the accumulation ofβ-ionone indicated that CsCCD1 may involve in the formation ofβ-ionone in 13 cultivars.Prokaryotic expression and in vitro enzyme activity assays showed that‘Chuanhuang 1’had an amino acid mutation in carotenoid cleavage dioxygenases 1(CsCCD1)compared with‘Shuchazao’,resulting in a significantly higherβ-ionone content in‘Chuanhuang 1’.Sequence analysis showed that‘Chuanhuang 1’and‘Huangdan’had different CsCCD1 promoter sequences,leading to significantly higher CsCCD1 expression andβ-ionone accumulation in‘Chuanhuang 1’.These results indicated that the promoter and coding sequence diversity of CsCCD1 might contribute to the differential accumulation ofβ-ionone in different tea cultivars.
基金supported by the National Natural Science Foundation of China(31961133030,31870678)National Key Research and Development Program of China(2018YFD1000601)Science Fund for Distinguished Young Scientists of Anhui Province(1908085J12).
文摘4-Hydroxy-2,5-dimethylfuran-3(2H)-one(HDMF)is an important odorant in some fruits,and is proposed to play a crucial role in the caramel-like notes of some teas.However,its biosynthesis and metabolism in tea plants are still unknown.Here,HDMF glucoside was unambiguously identified as a native metabolite in tea plants.A novel glucosyltransferase UGT74AF3a and its allelic protein UGT74AF3b specifically catalyzed the glucosylation of HDMF and the commercially important structural homologues 2(or 5)-ethyl-4-hydroxy-5(or 2)-methylfuran-3(2H)-one(EHMF)and 4-hydroxy-5-methylfuran-3(2H)-one(HMF)to their correspondingβ-D-glucosides.Site-directed mutagenesis of UGT74AF3b to introduce a single A456V mutation resulted in improved HDMF and EHMF glucosylation activity and affected the sugar donor preference compared with that of the wild-type control enzyme.The accumulation of HDMF glucoside was consistent with the transcript levels of UGT74AF3 in different tea cultivars.In addition,transient UGT74AF3a overexpression in tobacco significantly increased the HDMF glucoside contents,and downregulation of UGT74AF3 transcripts in tea leaves significantly reduced the concentration of HDMF glucoside compared with the levels in the controls.The identification of HDMF glucoside in the tea plant and the discovery of a novel-specific UDP-glucose:HDMF glucosyltransferase in tea plants provide the foundation for improvement of tea flavor and the biotechnological production of HDMF glucoside.
基金This research was financially supported by the Deutsche Forschungsgemeinschaft in frame of the project numbers AOBJ 575560 and AOBJ 575561.
文摘Lipoxygenase(LOX)is an important contributor to the formation of aroma-active C6 aldehydes in apple(Malus×domestica)fruit upon tissue disruption but little is known about its role in autonomously produced aroma volatiles from intact tissue.We explored the expression of 22 putative LOX genes in apple throughout ripening,but only six LOXs were expressed in a ripening-dependent manner.Recombinant LOX1:Md:1a,LOX1:Md:1c,LOX2:Md:2a and LOX2:Md:2b proteins showed 13/9-LOX,9-LOX,13/9-LOX and 13-LOX activity with linoleic acid,respectively.While products of LOX1:Md:1c and LOX2:Md:2b were S-configured,LOX1:Md:1a and LOX2:Md:2a formed 13(R)-hydroperoxides as major products.Site-directed mutagenesis of Gly567 to an alanine converted the dual positional specific LOX1:Md:1a to an enzyme with a high specificity for 9(S)-hydroperoxide formation.The high expression level of the corresponding MdLOX1a gene in stored apple fruit,the genetic association with a quantitative trait locus for fruit ester and the remarkable agreement in regio-and stereoselectivity of the LOX1:Md:1a reaction with the overall LOX activity found in mature apple fruits,suggest a major physiological function of LOX1:Md:1a during climacteric ripening of apples.While LOX1:Md:1c,LOX2:Md:2a and LOX2:Md:2b may contribute to aldehyde production in immature fruit upon cell disruption our results furnish additional evidence that LOX1:Md:1a probably regulates the availability of precursors for ester production in intact fruit tissue.
基金This work was financially supported by the National Natural Science Foundation of China(31961133030,31870678,32022076)the Science Fund for Distinguished Young Scientists of Anhui Province(1908085J12)the Deutsche Forschungsgemeinschaft(SCHW634/32-1 and SCHW634/34-1).
文摘Plants have developed sophisticated mechanisms to survive in dynamic environments.Plants can communicate via volatile organic compounds(VOCs)to warn neighboring plants of threats.In most cases,VOCs act as positive regulators of plant defense.However,the communication and role of volatiles in response to drought stress are poorly understood.Here,we showed that tea plants release numerous VOCs.Among them,methyl salicylate(MeSA),benzyl alcohol,and phenethyl alcohol markedly increased under drought stress.Interestingly,further experiments revealed that drought-induced MeSA lowered the abscisic acid(ABA)content in neighboring plants by reducing 9-cis-epoxycarotenoid dioxygenase(NCED)gene expression,resulting in inhibition of stomatal closure and ultimately decreasing early drought tolerance in neighboring plants.Exogenous application of ABA reduced the wilting of tea plants caused by MeSA exposure.Exposure of Nicotiana benthamiana to MeSA also led to severe wilting,indicating that the ability of drought-induced MeSA to reduce early drought tolerance in neighboring plants may be conserved in other plant species.Taken together,these results provide evidence that drought-induced volatiles can reduce early drought tolerance in neighboring plants and lay a novel theoretical foundation for optimizing plant density and spacing.
基金This work was supported by grants from the Spanish Ministry of Economy and Competitiveness(MINECO,BIO2013-44199-R)B.O-N.was supported by a FPI fellowship and C.M.by the RYC program of Spanish Ministry of Economy and CompetitivenessThe authors would like to thank and acknowledge the support of this work by the EU funded GoodBerry project(funded from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 679303).
文摘The strawberry Fra a 1 proteins belong to the class 10 Pathogenesis-Related(PR-10)superfamily.In strawberry,a large number of members have been identified,but only a limited number is expressed in the fruits.In this organ,Fra a 1.01 and Fra a 1.02 are the most abundant Fra proteins in the green and red fruits,respectively,however,their function remains unknown.To know the function of Fra a 1.02 we have generated transgenic lines that silence this gene,and performed metabolomics,RNA-Seq,and hormonal assays.Previous studies associated Fra a 1.02 to strawberry fruit color,but the analysis of anthocyanins in the ripe fruits showed no diminution in their content in the silenced lines.Gene ontology(GO)analysis of the genes differentially expressed indicated that oxidation/reduction was the most represented biological process.Redox state was not apparently altered since no changes were found in ascorbic acid and glutathione(GSH)reduced/oxidized ratio,but GSH content was reduced in the silenced fruits.In addition,a number of glutathione-S-transferases(GST)were down-regulated as result of Fra a 1.02-silencing.Another highly represented GO category was transport which included a number of ABC and MATE transporters.Among the regulatory genes differentially expressed WRKY33.1 and WRKY33.2 were down-regulated,which had previously been assigned a role in strawberry plant defense.A reduced expression of the VQ23 gene and a diminished content of the hormones JA,SA,and IAA were also found.These data might indicate that Fra a 1.02 participates in the defense against pathogens in the ripe strawberry fruits.
基金The National Natural Science Foundation of China(31870680)the China Agriculture Research System of MOF and MARA(CARS-19)+4 种基金the Key Research and Development Program of Jiangsu Province(BE2019379)Jiangsu Agriculture Science and Technology Innovation Fund(CX(20)2004)Innovation and Extension Projects of Forestry Science and Technology in Jiangsu Province(LYKJ-Changzhou[2020]03)Changzhou Science and Technology Support Program(Agriculture CE20202003)Chuzhou Science and Technology Support Program(2020ZN009).
文摘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.
基金This research was funded by National Key Research and Development Program of China(2021YFD1601103 and 2022YFF1003103)National Natural Science Foundation of China(31902075,32150017 and 32022076).
文摘Geraniol is an important contributor to the pleasant floral scent of tea products and one of the most abundant aroma compounds in tea plants;however,its biosynthesis and physiological function in response to stress in tea plants remain unclear.The proteins encoded by the full-length terpene synthase(CsTPS1)and its alternative splicing isoform(CsTPS1-AS)could catalyze the formation of geraniol when GPP was used as a substrate in vitro,whereas the expression of CsTPS1-AS was only significantly induced by Colletotrichum gloeosporioides and Neopestalotiopsis sp.infection.Silencing of CsTPS1 and CsTPS1-AS resulted in a significant decrease of geraniol content in tea plants.The geraniol content and disease resistance of tea plants were compared when CsTPS1 and CsTPS1-AS were silenced.Down-regulation of the expression of CsTPS1-AS reduced the accumulation of geraniol,and the silenced tea plants exhibited greater susceptibility to pathogen infection than control plants.However,there was no significant difference observed in the geraniol content and pathogen resistance between CsTPS1-silenced plants and control plants in the tea plants infected with two pathogens.Further analysis showed that silencing of CsTPS1-AS led to a decrease in the expression of the defense-related genes PR1 and PR2 and SA pathway-related genes in tea plants,which increased the susceptibility of tea plants to pathogens infections.Both in vitro and in vivo results indicated that CsTPS1 is involved in the regulation of geraniol formation and plant defense via alternative splicing in tea plants.The results of this study provide new insights into geraniol biosynthesis and highlight the role of monoterpene synthases in modulating plant disease resistance via alternative splicing.
基金supported by the European Union’s Horizon 2020 research and innovation program(GoodBerrygrant agreement number 679303)Agencia Estatal de Investigación(PID2019-111496RR-I00/AEI/10.13039/501100011033)and PR.AVA.AVA2019.034(IFAPA,FEDER funds)。
文摘Strawberry(Fragaria×ananassa)fruits are an excellent source of L-ascorbic acid(AsA),a powerful antioxidant for plants and humans.Identifying the genetic components underlying AsA accumulation is crucial for enhancing strawberry nutritional quality.Here,we unravel the genetic architecture of AsA accumulation using an F1 population derived from parental lines‘Candonga’and‘Senga Sengana’,adapted to distinct Southern and Northern European areas.To account for environmental effects,the F1 and parental lines were grown and phenotyped in five locations across Europe(France,Germany,Italy,Poland and Spain).Fruit AsA content displayed normal distribution typical of quantitative traits and ranged five-fold,with significant differences among genotypes and environments.AsA content in each country and the average in all of them was used in combination with 6,974 markers for quantitative trait locus(QTL)analysis.Environmentally stable QTLs for AsA content were detected in linkage group(LG)3A,LG 5A,LG 5B,LG 6B and LG 7C.Candidate genes were identified within stable QTL intervals and expression analysis in lines with contrasting AsA content suggested that GDP-L-Galactose Phosphorylase FaGGP(3A),and the chloroplast-located AsA transporter gene FaPHT4;4(7C)might be the underlying genetic factors for QTLs on LG 3A and 7C,respectively.We show that recessive alleles of FaGGP(3A)inherited from both parental lines increase fruit AsA content.Furthermore,expression of FaGGP(3A)was two-fold higher in lines with high AsA.Markers here identified represent a useful resource for efficient selection of new strawberry cultivars with increased AsA content.
基金supported by the National Key Research and Development Program of China(2022YFF1003103)the National Natural Science Foundation of China(U22A20499 and 32022076)+1 种基金the Deutsche Forschungsgemeinschaft(DFG SCHW 634/34-1)the China Postdoctoral Science Foundation 2022 M720193。
文摘Plants respond to environmental stimuli via the release of volatile organic compounds(VOCs),and neighboring plants constantly monitor and respond to these VOCs with great sensitivity and discrimination.This sensing can trigger increased plant fitness and reduce future plant damage through the priming of their own defenses.The defense mechanism in neighboring plants can either be induced by activation of the regulatory or transcriptional machinery,or it can be delayed by the absorption and storage of VOCs for the generation of an appropriate response later.Despite much research,many key questions remain on the role of VOCs in interplant communication and plant fitness.Here we review recent research on the VOCs induced by biotic(i.e.insects and pathogens)and abiotic(i.e.cold,drought,and salt)stresses,and elucidate the biosynthesis of stress-induced VOCs in tea plants.Our focus is on the role of stress-induced VOCs in complex ecological environments.Particularly,the roles of VOCs under abiotic stress are highlighted.Finally,we discuss pertinent questions and future research directions for advancing our understanding of plant interactions via VOCs.
文摘Uridine diphosphate-dependent glycosyltransferases(UGTs)mediate the glycosylation of plant metabolites,thereby altering their physicochemical properties and bioactivities.Plants possess numerous UGT genes,with the encoded enzymes often glycosylating multiple substrates and some exhibiting substrate inhibition kinetics,but the biological function and molecular basis of these phenomena are not fully understood.The promiscuous monolignol/phytoalexin glycosyltransferase NbUGT72AY1 exhibits substrate inhibition(Ki)at 4 mM scopoletin,whereas the highly homologous monolignol StUGT72AY2 is inhibited at 190 mM.We therefore used hydrogen/deuterium exchange mass spectrometry and structure-based mutational analyses of both proteins and introduced NbUGT72AY1 residues into StUGT72AY2 and vice versa to study promiscuity and substrate inhibition of UGTs.A single F87I and chimeric mutant of NbUGT72AY1 showed significantly reducedscopoletin substrate inhibition,whereas its monolignolgly cosylation activity was almost unaffected.Reverse mutations in StUGT72AY2 resulted in increased scopoletin glycosylation,leading to enhanced promiscuity,which was accompanied by substrate inhibition.Studies of 3D structures identified open and closed UGT conformers,allowing visualization of the dynamics of conformational changes that occur during catalysis.Previously postulated substrate access tunnels likely serve as drainage channels.The results suggest a two-site model in which the second substrate molecule binds near the catalytic site and blocks product release.Mutational studies showed that minor changes in amino acid sequence can enhance the promiscuity of the enzyme and add new capabilities such as substrate inhibition without affecting existing functions.The proposed subfunctionalization mechanism of expanded promiscuity may play a role in enzyme evolution and highlights the importance of promiscuous enzymes in providing new functions.
基金This work was supported by the Deutsche Forschungsgemeinschaft DFG （SCHW634/32-1） and National Natural Science Foundation of China （grant numbers 31870678）.
基金supported by the National Key Research and Development Program of China(2018YFD1000601)National Natural Science Founda-tion of China(31961133030,31870678)Science Fundfor Distinguished Young Scientists of Anhui Province(1908085J12).
文摘Plants have evolved sophisticated defense mechanisms to overcome their sessile nature.However,if and how volatiles from cold‐stressed plants can trigger interplant communication is still unknown.Here,we provide the first evidence for interplant communication via inducible volatiles in cold stress.The volatiles,including nerolidol,geraniol,linalool,and methyl salicylate,emitted from cold‐stressed tea plants play key role(s)in priming cold tolerance of their neighbors via a C‐repeatbinding factors‐dependent pathway.The knowledge will help us to understand how plants respond to volatile cues in cold stress and agricultural ecosystems.
