The Paeonia qiui R2R3-MYB Transcription Factor PqMYB113 Positively Regulates Anthocyanin Accumulation in Arabidopsis thaliana and Tobacco.
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ABSTRACT:
SUBMITTER: Liu X
PROVIDER: S-EPMC8789887 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Paeonia qiui is a wild tree peony native to China. Its leaves show a clear purple-red color from the germination to the flowering stage, and it has high leaf-viewing value. A MYB transcription factor gene, designated as PqMYB4, was isolated from leaves of P. qiui based on transcriptome datas. The full-length cDNA of PqMYB4 was 693 bp, encoding 230 amino acids. Sequence alignment and phylogenetic analysis revealed that PqMYB4 was a R2R3-MYB transcription factor clustered with AtMYB4 in Arabidopsis thaliana. Moreover, it contained a C1 motif, an EAR repression motif and a TLLLFR motif in the C-terminal domains, which were unique in transcription repression MYB. Subcellular location analysis showed that PqMYB4 was located in the cell nucleus. PqMYB4 was highly expressed in the late stage of leaf development, and was negatively correlated with the anthocyanin content. The petiole of wild-type Arabidopsis seedlings was deeper in color than the transgenic lines of PqMYB4 and showed a little purple-red color. The seed coat color of Arabidopsis seeds that overexpressed PqMYB4 gene was significantly lighter than that of wild-type seeds. In transgenic Arabidopsis, the expression level of AtCHS, AtCHI, AtDFR and AtANS were down-regulated significantly. These results showed that PqMYB4 was involved in the negative regulation of anthocyanin biosynthesis in tree peony leaves, which can control the anthocyanin pathway genes. Together, these findings provide a valuable resource with which to further study the regulatory mechanism of anthocyanin biosynthesis in the leaf of P. qiui. They also benefit the molecular breeding of tree peony cultivars with colored leaf.
| S-EPMC7461502 | biostudies-literature
Project description:The generation of chrysanthemum (Chrysanthemum × morifolium) flower color is mainly attributed to the accumulation of anthocyanins. In the anthocyanin biosynthetic pathway in chrysanthemum, although all of the structural genes have been cloned, the regulatory function of R2R3-MYB transcription factor (TF) genes, which play a crucial role in determining anthocyanin accumulation in many ornamental crops, still remains unclear. In our previous study, four light-induced R2R3-MYB TF genes in chrysanthemum were identified using transcriptomic sequencing. In the present study, we further investigated the regulatory functions of these genes via phylogenetic and alignment analyses of amino acid sequences, which were subsequently verified by phenotypic, pigmental, and structural gene expression analyses in transgenic tobacco lines. As revealed by phylogenetic and alignment analyses, CmMYB4 and CmMYB5 were phenylpropanoid and flavonoid repressor R2R3-MYB genes, respectively, while CmMYB6 was an activator of anthocyanin biosynthesis, and CmMYB7 was involved in regulating flavonol biosynthesis. Compared with wild-type plants, the relative anthocyanin contents in the 35S:CmMYB4 and 35S:CmMYB5 tobacco lines significantly decreased (p < 0.05), while for 35S:CmMYB6 and 35S:CmMYB7, the opposite result was obtained. Both in the 35S:CmMYB4 and 35S:CmMYB5 lines, the relative expression of several anthocyanin biosynthetic genes in tobacco was significantly downregulated (p < 0.05); on the contrary, several genes were upregulated in the 35S:CmMYB6 and 35S:CmMYB7 lines. These results indicate that CmMYB4 and CmMYB5 negatively regulate anthocyanin biosynthesis in chrysanthemum, while CmMYB6 and CmMYB7 play a positive role, which will aid in understanding the complex mechanism regulating floral pigmentation in chrysanthemum and the functional divergence of the R2R3-MYB gene family in higher plants.
| S-EPMC6826627 | biostudies-literature
Project description:The level of anthocyanins in plants vary widely among cultivars, developmental stages and environmental stimuli. Previous studies have reported that the expression of various MYBs regulate anthocyanin pigmentation during growth and development. Here we examine the activity of 3 novel R2R3-MYB transcription factor (TF) genes, PamMybA.1, PamMybA.3 and PamMybA.5 from Prunus americana. The anthocyanin accumulation patterns mediated by CaMV double35S promoter (db35Sp) controlled expression of the TFs in transgenic tobacco were compared with citrus-MoroMybA, Arabidopsis-AtMybA1 and grapevine-VvMybA1 transgenics during their entire growth cycles. The db35Sp-PamMybA.1 and db35Sp-PamMybA.5 constructs induced high levels of anthocyanin accumulation in both transformed tobacco calli and the regenerated plants. The red/purple color pigmentation induced in the PamMybA.1 and PamMybA.5 lines was not uniformly distributed, but appeared as patches in the leaves, whereas the flowers showed intense uniform pigmentation similar to the VvMybA1 expressing lines. MoroMybA and AtMybA1 showed more uniform pink coloration in both vegetative and reproductive tissues. Plant morphology, anthocyanin content, seed viability, and transgene inheritance were examined for the PamMybA.5 transgenic plants and compared with the controls. We conclude that these TFs alone are sufficient for activating anthocyanin production in plants and may be used as visible reporter genes for plant transformation. Evaluating these TFs in a heterologous crop species such as citrus further validated that these genes can be useful for the metabolic engineering of anthocyanin production and cultivar enhancement.
| S-EPMC5443614 | biostudies-literature
Project description:Flower color is a charming phenotype with very important ornamental and commercial values. Anthocyanins play a critical role in determining flower color pattern formation, and their biosynthesis is typically regulated by R2R3-MYB transcription factors (TFs). Paeonia suffruticosa is a famous ornamental plant with colorful flowers. However, little is known about the R2R3-MYB TFs that regulate anthocyanin accumulation in P. suffruticosa. In the present study, two R2R3-MYB TFs, namely, PsMYB114L and PsMYB12L, were isolated from the petals of P. suffruticosa 'Shima Nishiki' and functionally characterized. Sequence analysis suggested that PsMYB114L contained a bHLH-interaction motif, whereas PsMYB12L contained two flavonol-specific motifs (SG7 and SG7-2). Subsequently, the in vivo function of PsMYB114L and PsMYB12L was investigated by their heterologous expression in Arabidopsis thaliana and apple calli. In transgenic Arabidopsis plants, overexpression of PsMYB114L and of PsMYB12L caused a significantly higher accumulation of anthocyanins, resulting in purple-red leaves. Transgenic apple calli overexpressing PsMYB114L and PsMYB12L also significantly enhanced the anthocyanins content and resulted in a change in the callus color to red. Meanwhile, gene expression analysis in A. thaliana and apple calli suggested that the expression levels of the flavonol synthase (MdFLS) and anthocyanidin reductase (MdANR) genes were significantly downregulated and the dihydroflavonol 4-reductase (AtDFR) and anthocyanin synthase (AtANS) genes were significantly upregulated in transgenic lines of PsMYB114L. Moreover, the expression level of the FLS gene (MdFLS) was significantly downregulated and the DFR (AtDFR/MdDFR) and ANS (AtANS/MdANS) genes were all significantly upregulated in transgenic lines plants of PsMYB12L. These results indicate that PsMYB114L and PsMYB12L both enhance anthocyanin accumulation by specifically regulating the expression of some anthocyanin biosynthesis-related genes in different plant species. Together, these results provide a valuable resource with which to further study the regulatory mechanism of anthocyanin biosynthesis in P. suffruticosa and for the breeding of tree peony cultivars with novel and charming flower colors.
| S-EPMC6429501 | biostudies-literature
Project description:Lonicera japonica Thunb. is a widely used medicinal plant and is rich in a variety of active ingredients. Flavonoids are one of the important components in L. japonica and their content is an important indicator for evaluating the quality of this herb. To study the regulation of flavonoid biosynthesis in L. japonica, an R2R3-MYB transcription factor gene LjaMYB12 was isolated and characterized. Bioinformatics analysis indicated that LjaMYB12 belonged to the subgroup 7, with a typical R2R3 DNA-binding domain and conserved subgroup 7 motifs. The transcriptional level of LjaMYB12 was proportional to the total flavonoid content during the development of L. japonica flowers. Subcellular localization analysis revealed that LjaMYB12 localized to the nucleus. Transactivation activity assay indicated that LjaMYB12 was a transcriptional activator. Then, ectopic expression of LjaMYB12 in Arabidopsis could increase PAL activity and flavonoid content and promote transcription of a range of flavonoid biosynthetic genes. Interestingly, the fold changes of downstream genes in the flavonoid biosynthetic pathway were significantly higher than that of the upstream genes, which suggested that LjaMYB12 may have different regulatory patterns for the upstream and downstream pathways of flavonoid biosynthesis. The results provided here will effectively facilitate the study of subgroup 7 MYBs and transcriptional regulation of flavonoid biosynthesis in L. japonica.
| S-EPMC6770605 | biostudies-literature
Project description:Anthocyanin accumulation is responsible for flower coloration in peach. Here, we report the identification and functional characterization of eight flavonoid-related R2R3-MYB transcription factors, designated PpMYB10.2, PpMYB9, PpMYBPA1, Peace, PpMYB17, PpMYB18, PpMYB19, and PpMYB20, respectively, in peach flower transcriptome. PpMYB10.2 and PpMYB9 are able to activate transcription of anthocyanin biosynthetic genes, whilst PpMYBPA1 and Peace have a strong activation on the promoters of proanthocyanin (PA) biosynthetic genes. PpMYB17-20 show a strong repressive effect on transcription of flavonoid pathway genes such as dihydroflavonol 4-reductase. These results indicate that anthocyanin accumulation in peach flower is coordinately regulated by a set of R2R3-MYB genes. In addition, PpMYB9 and PpMYB10.2 are closely related but separated into two groups, designated MYB9 and MYB10, respectively. PpMYB9 shows a strong activation on the PpUGT78A2 promoter, but with no effect on the promoter of PpUGT78B (commonly called PpUFGT in previous studies). In contrast, PpMYB10.2 is able to activate the PpUFGT promoter, but not for the PpUGT78A2 promoter. Unlike the MYB10 gene that is universally present in plants, the MYB9 gene is lost in most dicot species. Therefore, the PpMYB9 gene represents a novel group of anthocyanin-related MYB activators, which may have diverged in function from the MYB10 genes. Our study will aid in understanding the complex mechanism regulating floral pigmentation in peach and functional divergence of the R2R3-MYB gene family in plants.
| S-EPMC5073212 | biostudies-literature
Project description:The genes MYB11, MYB12 and MYB111 share significant structural similarity and form subgroup 7 of the Arabidopsis thaliana R2R3-MYB gene family. To determine the regulatory potential of these three transcription factors, we used a combination of genetic, functional genomics and metabolite analysis approaches. MYB11, MYB12 and MYB111 show a high degree of functional similarity and display very similar target gene specificity for several genes of flavonoid biosynthesis, including CHALCONE SYNTHASE, CHALCONE ISOMERASE, FLAVANONE 3-HYDROXYLASE and FLAVONOL SYNTHASE1. Seedlings of the triple mutant myb11 myb12 myb111, which genetically lack a complete subgroup of R2R3-MYB genes, do not form flavonols while the accumulation of anthocyanins is not affected. In developing seedlings, MYB11, MYB12 and MYB111 act in an additive manner due to their differential spatial activity; MYB12 controls flavonol biosynthesis mainly in the root, while MYB111 controls flavonol biosynthesis primarily in cotyledons. We identified and confirmed additional target genes of the R2R3-MYB subgroup 7 factors, including the UDP-glycosyltransferases UGT91A1 and UGT84A1, and we demonstrate that the accumulation of distinct and structurally identified flavonol glycosides in seedlings correlates with the expression domains of the different R2R3-MYB factors. Therefore, we refer to these genes as PFG1-3 for 'PRODUCTION OF FLAVONOL GLYCOSIDES'.
| S-EPMC1976380 | biostudies-literature
Project description:Anthocyanins widely accumulate in the vegetative and reproductive tissues of strawberries and play an important role in stress resistance and fruit quality. Compared with other fruits, little is known about the molecular mechanisms regulating anthocyanin accumulation in strawberry vegetative tissues. In this study, we revealed an R2R3-MYB transcription factor, FaMYB10-like (FaMYB10L), which positively regulated anthocyanin accumulation and was induced by light in the petiole and runner of cultivated strawberry. FaMYB10L is a homologue of FveMYB10-like and a nuclear localization protein. Transient overexpression of FaMYB10L in a white fruit strawberry variety (myb10 mutant) rescued fruit pigmentation, and further qR-PCR analysis revealed that FaMYB10L upregulated the expression levels of anthocyanin biosynthesis-related genes and transport gene. A dual luciferase assay showed that FaMYB10L could activate the anthocyanin transport gene FaRAP. Anthocyanin accumulation was observed in FaMYB10L-overexpressing strawberry calli, and light treatment enhanced anthocyanin accumulation. Furthermore, transcriptomic profiling indicated that the DEGs involved in the flavonoid biosynthesis pathway and induced by light were enriched in FaMYB10L-overexpressing strawberry calli. In addition, yeast two-hybrid assays and luciferase complementation assays indicated that FaMYB10L could interact with bHLH3. These findings enriched the light-involved regulatory network of anthocyanin metabolism in cultivated strawberries.
| S-EPMC10706590 | biostudies-literature
Project description: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 (Gerberahybrida). 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 (Nicotianatabacum) 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.
| S-EPMC7237480 | biostudies-literature
Project description:Anthocyanins are responsible for the different colors of ornamental plants. Grape hyacinth (Muscari armeniacum), a monocot plant with bulbous flowers, is popular for its fascinating blue color. In the present study, we functionally characterized an R2R3-MYB transcription factor gene MaAN2 from M. armeniacum. Our results indicated that MaAN2 participates in controlling anthocyanin biosynthesis. Sequence alignment and phylogenetic analysis suggested that MaAN2 belonged to the R2R3-MYB family AN2 subgroup. The anthocyanin accumulation of grape hyacinth flowers was positively correlated with the expression of MaAN2. And the transcriptional expression of MaAN2 was also consistent with that of M. armeniacum dihydroflavonol 4-reductase (MaDFR) and M. armeniacum anthocyanidin synthase (MaANS) in flowers. A dual luciferase transient expression assay indicated that when MaAN2 was co-inflitrated with Arabidopsis thaliana TRANSPARENT TESTA8 (AtTT8), it strongly activated the promoters of MaDFR and MaANS, but not the promoters of M. armeniacum chalcone synthase (MaCHS), M. armeniacum chalcone isomerase (MaCHI), and M. armeniacum flavanone 3-hydroxylase (MaF3H). Bimolecular fluorescence complementation assay confirmed that MaAN2 interacted with AtTT8 in vivo. The ectopic expression of MaAN2 in Nicotiana tabacum resulted in obvious red coloration of the leaves and much redder flowers. Almost all anthocyanin biosynthetic genes were remarkably upregulated in the leaves and flowers of the transgenic tobacco, and NtAn1a and NtAn1b (two basic helix-loop-helix anthocyanin regulatory genes) were highly expressed in the transformed leaves, compared to the empty vector transformants. Collectively, our results suggest that MaAN2 plays a role in anthocyanin biosynthesis.
| S-EPMC5462982 | biostudies-literature