Paeonia species are important ornamental plants,including three types:tree peony,herbaceous peony,and Itoh hybrid peony.Paeonia with yellow color is desired and becoming popular.However,the chemical mechanism of the f...Paeonia species are important ornamental plants,including three types:tree peony,herbaceous peony,and Itoh hybrid peony.Paeonia with yellow color is desired and becoming popular.However,the chemical mechanism of the formation of yellow flowers in Paeonia is still unclear.In this study,14 representative samples were selected:four samples of three species of Paeonia,four herbaceous peony cultivars,three lutea hybrid tree peony cultivars,and three Itoh hybrid peony cultivars.The petal extracts of the samples were determined by HPLC-DAD and HPLCQ-TOF-MS/MS.In total,29 flavonoids were isolated and identified,including 28 flavonol glycosides and one chalcone derivative.There were significant differences in the composition and content of flavonoids in petals of different cultivars(species).The total content of flavonoids was between 19.430 and 143.043 mg·g^−1 DW.Flavonol glycosides were detected in all samples.Chalconaringenin 2′-O-glucoside was detected from one herbaceous peony cultivar‘Golden Wheel’lutea hybrid tree peony cultivars,and Itoh peony cultivars.The content of chalconaringenin 2′-O-glucoside in the samples was more than 43% of total flavonoids.The pigment type and content of lutea hybrid tree peonies and Itoh hybrid peonies are similar.Total flavonoids,especially quercetin 3-O-galloylglucoside and chalconaringenin 2′-O-glucoside contribute greatly to the formation of yellow flowers of Paeonia.The results of this study provide a comprehensive understanding of the chemical mechanism for yellow flower coloration of Paeonia,and lay the foundation for yellow flower breeding of Paeonia.展开更多
Anthocyanins and flavonols have vital roles in flower coloration,plant development,and defense.Because anthocyanins and flavonols share the same subcellular localization and common biosynthetic substrates,these pathwa...Anthocyanins and flavonols have vital roles in flower coloration,plant development,and defense.Because anthocyanins and flavonols share the same subcellular localization and common biosynthetic substrates,these pathways may compete for substrates.However,the mechanism regulating this potential competition remains unclear.Here,we identified GhMYB1a,an R2R3-MYB transcription factor involved in the regulation of anthocyanin and flavonol accumulation in gerbera(Gerbera hybrida).GhMYB1a shares high sequence similarity with that of other characterized regulators of flavonol biosynthesis.In addition,GhMYB1a is also phylogenetically grouped with these proteins.The overexpression of GhMYB1a in gerbera and tobacco(Nicotiana tabacum)resulted in decreased anthocyanin accumulation and increased accumulation of flavonols by upregulating the structural genes involved in flavonol biosynthesis.We further found that GhMYB1a functions as a homodimer instead of interacting with basic helix-loop-helix cofactors.These results suggest that GhMYB1a is involved in regulating the anthocyanin and flavonol metabolic pathways through precise regulation of gene expression.The functional characterization of GhMYB1a provides insight into the biosynthesis and regulation of flavonols and anthocyanins.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31772350).
文摘Paeonia species are important ornamental plants,including three types:tree peony,herbaceous peony,and Itoh hybrid peony.Paeonia with yellow color is desired and becoming popular.However,the chemical mechanism of the formation of yellow flowers in Paeonia is still unclear.In this study,14 representative samples were selected:four samples of three species of Paeonia,four herbaceous peony cultivars,three lutea hybrid tree peony cultivars,and three Itoh hybrid peony cultivars.The petal extracts of the samples were determined by HPLC-DAD and HPLCQ-TOF-MS/MS.In total,29 flavonoids were isolated and identified,including 28 flavonol glycosides and one chalcone derivative.There were significant differences in the composition and content of flavonoids in petals of different cultivars(species).The total content of flavonoids was between 19.430 and 143.043 mg·g^−1 DW.Flavonol glycosides were detected in all samples.Chalconaringenin 2′-O-glucoside was detected from one herbaceous peony cultivar‘Golden Wheel’lutea hybrid tree peony cultivars,and Itoh peony cultivars.The content of chalconaringenin 2′-O-glucoside in the samples was more than 43% of total flavonoids.The pigment type and content of lutea hybrid tree peonies and Itoh hybrid peonies are similar.Total flavonoids,especially quercetin 3-O-galloylglucoside and chalconaringenin 2′-O-glucoside contribute greatly to the formation of yellow flowers of Paeonia.The results of this study provide a comprehensive understanding of the chemical mechanism for yellow flower coloration of Paeonia,and lay the foundation for yellow flower breeding of Paeonia.
基金supported by the Foundation of Guangzhou Science and Technology Project(201904010127 to C.Z.)National Natural Science Foundation of China(Grants 31372099,31601784,and 31672188 to X.W.,L.L.and Y.W.,respectively)+1 种基金Open Project Foundation of South China Normal University(2018KF0202 to C.Z.)Specialized Research Fund for Graduate Students at South China Normal University(2014ssxm26).
文摘Anthocyanins and flavonols have vital roles in flower coloration,plant development,and defense.Because anthocyanins and flavonols share the same subcellular localization and common biosynthetic substrates,these pathways may compete for substrates.However,the mechanism regulating this potential competition remains unclear.Here,we identified GhMYB1a,an R2R3-MYB transcription factor involved in the regulation of anthocyanin and flavonol accumulation in gerbera(Gerbera hybrida).GhMYB1a shares high sequence similarity with that of other characterized regulators of flavonol biosynthesis.In addition,GhMYB1a is also phylogenetically grouped with these proteins.The overexpression of GhMYB1a in gerbera and tobacco(Nicotiana tabacum)resulted in decreased anthocyanin accumulation and increased accumulation of flavonols by upregulating the structural genes involved in flavonol biosynthesis.We further found that GhMYB1a functions as a homodimer instead of interacting with basic helix-loop-helix cofactors.These results suggest that GhMYB1a is involved in regulating the anthocyanin and flavonol metabolic pathways through precise regulation of gene expression.The functional characterization of GhMYB1a provides insight into the biosynthesis and regulation of flavonols and anthocyanins.
