FvbHLH9 Functions as a Positive Regulator of Anthocyanin Biosynthesis by Forming a HY5–bHLH9 Transcription Complex in Strawberry Fruits

2020 ◽  
Vol 61 (4) ◽  
pp. 826-837 ◽  
Author(s):  
Yang Li ◽  
Pengbo Xu ◽  
Guanqun Chen ◽  
Jun Wu ◽  
Zhongchi Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Promoter Region ◽  
Anthocyanin Biosynthesis ◽  
Anthocyanin Synthesis ◽  
Bhlh Transcription Factor ◽  
Anthocyanin Accumulation ◽  
Positive Regulator ◽  
Key Enzyme ◽  
Synergistic Regulation ◽  
Transient Overexpression

Abstract Anthocyanin accumulation is transcriptionally regulated by the MYB–bHLH–WD40 complex. Light is indispensable for anthocyanin accumulation, and light-inducible MYB and HY5 were considered to promote anthocyanin accumulation in many fruits. Whether and how light-inducible bHLH transcription factor and HY5 regulate anthocyanin synthesis in strawberry is unknown. In this study, we identified a bHLH transcription factor, FvbHLH9, which was induced by light as well as FvHY5, and found that, similar to FvHY5, the transient overexpression and interference FvbHLH9 in strawberry fruits can promote and decrease anthocyanin accumulation, respectively, indicating FvbHLH9 functions as a positive regulator of anthocyanin biosynthesis. Furthermore, we confirmed that both FvHY5 and FvbHLH9 specifically bind to the promoter region of some key enzyme genes, including FvDFR, and the expression of FvDFR was activated through the heterodimer formation between FvHY5 and FvbHLH9. Finally, we confirmed that FvbHLH9-promoted anthocyanin accumulation is dependent on HY5–bHLH heterodimerisation in Arabidopsis. Our findings provide insights into a mechanism involving the synergistic regulation of light-dependent coloration and anthocyanin biosynthesis via a HY5–bHLH heterodimer formed by the interaction of FvHY5 and FvbHLH9 in strawberry fruits.

scholarly journals The Light-Induced WD40-Repeat Transcription Factor DcTTG1 Regulates Anthocyanin Biosynthesis in Dendrobium candidum

2021 ◽  
Vol 12 ◽  
Author(s):  
Ning Jia ◽  
Jingjing Wang ◽  
Yajuan Wang ◽  
Wei Ye ◽  
Jiameng Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Molecular Mechanisms ◽  
Anthocyanin Biosynthesis ◽  
Raw Material ◽  
Anthocyanin Synthesis ◽  
Anthocyanin Content ◽  
Anthocyanin Accumulation ◽  
Wd40 Repeat ◽  
Strong Light ◽  
Dendrobium Candidum

Dendrobium candidum is used as a traditional Chinese medicine and as a raw material in functional foods. D. candidum stems are green or red, and red stems are richer in anthocyanins. Light is an important environmental factor that induces anthocyanin accumulation in D. candidum. However, the underlying molecular mechanisms have not been fully unraveled. In this study, we exposed D. candidum seedlings to two different light intensities and found that strong light increased the anthocyanin content and the expression of genes involved in anthocyanin biosynthesis. Through transcriptome profiling and expression analysis, we identified a WD40-repeat transcription factor, DcTTG1, whose expression is induced by light. Yeast one-hybrid assays showed that DcTTG1 binds to the promoters of DcCHS2, DcCHI, DcF3H, and DcF3′H, and a transient GUS activity assay indicated that DcTTG1 can induce their expression. In addition, DcTTG1 complemented the anthocyanin deficiency phenotype of the Arabidopsis thaliana ttg1-13 mutant. Collectively, our results suggest that light promotes anthocyanin accumulation in D. candidum seedlings via the upregulation of DcTTG1, which induces anthocyanin synthesis-related gene expression.

MYB_SH[AL]QKY[RF] transcription factors MdLUX and MdPCL-like promote anthocyanin accumulation through DNA hypomethylation and MdF3H activation in apple

2020 ◽  
Author(s):  
Wen-Fang Li ◽  
Gai-Xing Ning ◽  
Cun-Wu Zuo ◽  
Ming-Yu Chu ◽  
Shi-Jin Yang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Transcription Factors ◽  
Promoter Region ◽  
Anthocyanin Biosynthesis ◽  
Apple Fruit ◽  
Anthocyanin Synthesis ◽  
Mrna Levels ◽  
Anthocyanin Accumulation ◽  
Dna Hypomethylation ◽  
Fruit Skin

Abstract Heritable DNA methylation is a highly conserved epigenetic mark that is important for many biological processes. In a previous transcriptomic study on the fruit skin pigmentation of apple (Malus domestica Borkh.) cv. ‘Red Delicious’ (G0) and its four continuous-generation bud sport mutants including ‘Starking Red’ (G1), ‘Starkrimson’ (G2), ‘Campbell Redchief’ (G3) and ‘Vallee spur’ (G4), we identified MYB transcription factors (TFs) MdLUX and MdPCL-like involved in regulating anthocyanin synthesis. However, how these TFs ultimately determine the fruit skin colour traits remain elusive. Here, bioinformatics analysis revealed that MdLUX and MdPCL-like contained a well-conserved motif SH[AL]QKY[RF] in their C-terminal region and were located in the nucleus of onion epidermal cells. Overexpression of MdLUX and MdPCL-like in ‘Golden Delicious’ fruits, ‘Gala’ calli and Arabidopsis thaliana promoted the accumulation of anthocyanin, whereas MdLUX and MdPCL-like suppression inhibited anthocyanin accumulation in ‘Red Fuji’ apple fruit skin. Yeast one-hybrid assays revealed that MdLUX and MdPCL-like may bind to the promoter region of the anthocyanin biosynthesis gene MdF3H. Dual-luciferase assays indicated that MdLUX and MdPCL-like activated MdF3H. The whole-genome DNA methylation study revealed that the methylation levels of the mCG context at the upstream (i.e., promoter region) of MdLUX and MdPCL-like were inversely correlated with their mRNA levels and anthocyanin accumulation. Hence, the data suggest that MYB_SH[AL]QKY[RF] TFs MdLUX and MdPCL-like promote anthocyanin biosynthesis in apple fruit skins through the DNA hypomethylation of their promoter regions and the activation of the structural flavonoid gene MdF3H.

scholarly journals VvMYB15 and VvWRKY40 Positively Co-regulated Anthocyanin Biosynthesis in Grape Berries in Response to Root Restriction

2021 ◽  
Vol 12 ◽  
Author(s):  
Dongmei Li ◽  
Zhenping Wang ◽  
Sijie Sun ◽  
Kun Xiao ◽  
Minghao Cao ◽  
...  
Keyword(s):  
Anthocyanin Biosynthesis ◽  
High Water ◽  
Economic Benefits ◽  
Grape Berry ◽  
Anthocyanin Synthesis ◽  
Anthocyanin Accumulation ◽  
Grape Berries ◽  
Transcriptional Regulatory ◽  
Transient Overexpression ◽  
Root Restriction

In most grapevine planting regions, especially in south of China, plenty of rainfall and high water level underground are the characteristic of the area, a series of problem during fruit ripening easily caused poor color quality. Thereby affecting fruit quality, yield and economic benefits. The accumulation of anthocyanin is regulated by transcriptional regulatory factor and a series of cultivation measures, root restriction can make plants in the environment of stress and stress relief, root restriction induced the higher expression of VvMYB15 and VvWRKY40, and consistent with anthocyanin accumulation. Whether and how root restriction-inducible VvMYB15 and VvWRKY40 transcription factor regulate anthocyanin synthesis in grape berry is still unclear. In this study, we identified that the transient overexpression of VvMYB15 and VvWRKY40 alone or both in strawberry fruits and grape berries can promote anthocyanin accumulation and increase the expression level of anthocyanin biosynthetic genes, indicating VvMYB15 and VvWRKY40 play a positive regulator of anthocyanin biosynthesis. Furthermore, we confirmed that both VvMYB15 and VvWRKY40 specifically bind to the promoter region of VvF3′5′H and VvUFGT, and the expression of VvF3′5′H and VvUFGT is further activated through the heterodimer formation between VvMYB15 and VvWRKY40. Finally, we confirmed that VvMYB15 promoted anthocyanin accumulation by interacting with VvWRKY40 in grape berries, our findings provide insights into a mechanism involving the synergistic regulation of root restriction-dependent coloration and biosynthesis via a VvMYB15 and VvWRKY40 alone or both in grape berries.

scholarly journals Genome-Wide Characterization and Analysis of bHLH Transcription Factors Related to Anthocyanin Biosynthesis in Fig (Ficus carica L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Miaoyu Song ◽  
Haomiao Wang ◽  
Zhe Wang ◽  
Hantang Huang ◽  
Shangwu Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Expression Patterns ◽  
Ficus Carica ◽  
Functional Study ◽  
Anthocyanin Synthesis ◽  
Bhlh Transcription Factor ◽  
Transcription Factor Family ◽  
Genome Database ◽  
Bhlh Genes

The basic helix–loop–helix (bHLH) transcription factor family is the second largest transcription factor family in plants, and participates in various plant growth and development processes. A total of 118 bHLH genes were identified from fig (Ficus carica L.) by whole-genome database search. Phylogenetic analysis with Arabidopsis homologs divided them into 25 subfamilies. Most of the bHLHs in each subfamily shared a similar gene structure and conserved motifs. Seventy-two bHLHs were found expressed at fragments per kilobase per million mapped (FPKM) > 10 in the fig fruit; among them, 15 bHLHs from eight subfamilies had FPKM > 100 in at least one sample. bHLH subfamilies had different expression patterns in the female flower tissue and peel during fig fruit development. Comparing green and purple peel mutants, 13 bHLH genes had a significantly different (≥ 2-fold) expression. Light deprivation resulted in 68 significantly upregulated and 22 downregulated bHLH genes in the peel of the fruit. Sixteen bHLH genes in subfamily III were selected by three sets of transcriptomic data as candidate genes related to anthocyanin synthesis. Interaction network prediction and yeast two-hybrid screening verified the interaction between FcbHLH42 and anthocyanin synthesis-related genes. The transient expression of FcbHLH42 in tobacco led to an apparent anthocyanin accumulation. Our results confirm the first fig bHLH gene involved in fruit color development, laying the foundation for an in-depth functional study on other FcbHLH genes in fig fruit quality formation, and contributing to our understanding of the evolution of bHLH genes in other horticulturally important Ficus species.

scholarly journals Conserved and non-conserved functions of the rice homologs of the Arabidopsis trichome initiation-regulating MBW complex proteins

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kaijie Zheng ◽  
Xutong Wang ◽  
Yating Wang ◽  
Shucai Wang
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Transcriptional Activator ◽  
Myb Transcription Factor ◽  
Bhlh Transcription Factor ◽  
Seed Color ◽  
Transcription Activator ◽  
Root Hair Formation ◽  
Protoplast Transfection ◽  
Mbw Complex

Abstract Background Trichome initiation in Arabidopsis is regulated by a MYB-bHLH-WD40 (MBW) transcriptional activator complex formed by the R2R3 MYB transcription factor GLABRA1 (GL1), MYB23 or MYB82, the bHLH transcription factor GLABRA3 (GL3), ENHANCER OF GLABRA3 (EGL3) or TRANSPARENT TESTA8 (TT8), and the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1). However, the functions of the rice homologs of the MBW complex proteins remained uncharacterized. Results Based on amino acid sequence identity and similarity, and protein interaction prediction, we identified OsGL1s, OsGL3s and OsTTG1s as rice homologs of the MBW complex proteins. By using protoplast transfection, we show that OsGL1D, OsGL1E, OsGL3B and OsTTG1A were predominantly localized in the nucleus, OsGL3B functions as a transcriptional activator and is able to interact with GL1 and TTG1. By using yeast two-hybrid and protoplast transfection assays, we show that OsGL3B is able to interact with OsGL1E and OsTTG1A, and OsGL1E and OsTTG1A are also able to interact with GL3. On the other hand, we found that OsGL1D functions as a transcription activator, and it can interact with GL3 but not OsGL3B. Furthermore, our results show that expression of OsTTG1A in the ttg1 mutant restored the phenotypes including alternations in trichome and root hair formation, seed color, mucilage production and anthocyanin biosynthesis, indicating that OsTTG1A and TTG1 may have similar functions. Conclusion These results suggest that the rice homologs of the Arabidopsis MBW complex proteins are able to form MBW complexes, but may have conserved and non-conserved functions.

scholarly journals The Isolation and Identification of Anthocyanin-Related GSTs in Chrysanthemum

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 231
Author(s):  
Yajing Li ◽  
Xiaofen Liu ◽  
Fang Li ◽  
Lili Xiang ◽  
Kunsong Chen
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Vital Role ◽  
Luciferase Assay ◽  
Amino Acid Residues ◽  
Anthocyanin Accumulation ◽  
Isolation And Identification ◽  
Specific Amino Acid ◽  
Protein Sequence Alignment ◽  
Glutathione S Transferases ◽  
Transient Overexpression

Anthocyanin is the crucial pigment for the coloration of red chrysanthemum flowers, which synthesizes in the cytosol and is transported to the vacuole for stable storage. In general, glutathione S-transferases (GSTs) play a vital role in this transport. To date, there is no functional GST reported in chrysanthemums. Here, a total of 94 CmGSTs were isolated from the chrysanthemum genome, with phylogenetic analysis suggesting that 16 members of them were clustered into the Phi subgroup which was related to anthocyanin transport. Among them, the expression of CmGST1 was positively correlated with anthocyanin accumulation. Protein sequence alignment revealed that CmGST1 included anthocyanin-related GST-specific amino acid residues. Further transient overexpression experiments in tobacco leaves showed that CmGST1 could promote anthocyanin accumulation. In addition, a dual-luciferase assay demonstrated that CmGST1 could be regulated by CmMYB6, CmbHLH2 and CmMYB#7, which was reported to be related to anthocyanin biosynthesis. Taken together, we suggested that CmGST1 played a key role in anthocyanin transport and accumulation in chrysanthemums.

scholarly journals PbGA2ox8 induces vascular-related anthocyanin accumulation and contributes to red stripe formation on pear fruit

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rui Zhai ◽  
Zhigang Wang ◽  
Chengquan Yang ◽  
Kui Lin-Wang ◽  
Richard Espley ◽  
...  
Keyword(s):  
Promoter Region ◽  
Vascular Bundles ◽  
Anthocyanin Accumulation ◽  
Comparative Transcriptome ◽  
Wild Type ◽  
Pear Fruit ◽  
Gene Encoding ◽  
Fruit Skin ◽  
Bud Sport ◽  
Transient Overexpression

AbstractFruit with stripes, which are generally longitudinal, can occur naturally, but the bioprocesses underlying this phenomenon are unclear. Previously, we observed an atypical anthocyanin distribution that caused red-striped fruit on the spontaneous pear bud sport “Red Zaosu” (Pyrus bretschneideri Rehd.). In this study, comparative transcriptome analysis of the sport and wild-type “Zaosu” revealed that this atypical anthocyanin accumulation was tightly correlated with abnormal overexpression of the gene-encoding gibberellin (GA) 2-beta-dioxygenase 8, PbGA2ox8. Consistently, decreased methylation was also observed in the promoter region of PbGA2ox8 from “Red Zaosu” compared with “Zaosu”. Moreover, the GA levels in “Red Zaosu” seedlings were lower than those in “Zaosu” seedlings, and the application of exogenous GA4 reduced abnormal anthocyanin accumulation in “Red Zaosu”. Transient overexpression of PbGA2ox8 reduced the GA4 level and caused anthocyanin accumulation in pear fruit skin. Moreover, the presence of red stripes indicated anthocyanin accumulation in the hypanthial epidermal layer near vascular branches (VBs) in “Red Zaosu”. Transient overexpression of PbGA2ox8 resulting from vacuum infiltration induced anthocyanin accumulation preferentially in calcium-enriched areas near the vascular bundles in pear leaves. We propose a fruit-striping mechanism, in which the abnormal overexpression of PbGA2ox8 in “Red Zaosu” induces the formation of a longitudinal array of anthocyanin stripes near vascular bundles in fruit.

Potato MYB and bHLH transcription factors associated with anthocyanin intensity and common scab resistance

Botany ◽  
2013 ◽  
Vol 91 (10) ◽  
pp. 722-730 ◽  
Author(s):  
Helen H. Tai ◽  
Claudia Goyer ◽  
Agnes M. Murphy
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Common Scab ◽  
Scab Resistance ◽  
Bhlh Transcription Factor ◽  
Bhlh Genes ◽  
Transcription Factor Genes ◽  
Key Enzyme ◽  
Common Scab Resistance ◽  
Highly Correlated

MYB and bHLH are large transcription factor families with largely uncharacterized biological functions. The patterns of expression of 42 MYB and 58 bHLH transcription factor genes were examined in potato clones that were demonstrated to have variation in anthocyanin intensity and common scab resistance to assess their possible involvement in regulating these traits. The control of expression of biosynthetic enzymes in regulation of anthocyanin intensity was also evaluated. The dihydroflavonol 4-reductase (DFR) gene, a key enzyme in the pathway, had the highest correlation with gene expression and anthocyanin intensity (quantified as levels of anthocyanidins). Expression of five uncharacterized MYB and three bHLH genes was also highly correlated with anthocyanin intensity, suggesting that they could be regulators of biosynthetic enzyme gene expression. The same potato clones were also demonstrated to have variation in resistance to Streptomyces scabiei, the causal pathogen of common scab in potato. Correlation analysis was used to show that anthocyanin intensity was not associated with common scab resistance. However, common scab resistance was correlated with expression of another two MYB and three bHLH genes, indicating that they might be involved in the regulation of the defense response of potato against the common scab pathogen.

scholarly journals CsMYB3 and CsRuby1 form an ‘Activator-and-Repressor’ Loop for the Regulation of Anthocyanin Biosynthesis in Citrus

2019 ◽  
Vol 61 (2) ◽  
pp. 318-330 ◽  
Author(s):  
Ding Huang ◽  
Zhouzhou Tang ◽  
Jialing Fu ◽  
Yue Yuan ◽  
Xiuxin Deng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Myb Transcription Factor ◽  
Nitrogen Stress ◽  
Loop Model ◽  
Anthocyanin Accumulation ◽  
Promoter Activation ◽  
R2r3 Myb ◽  
Activation Capacity ◽  
Anthocyanin Biosynthetic Genes

Abstract Anthocyanins are preferentially accumulated in certain tissues of particular species of citrus. A R2R3-MYB transcription factor (named Ruby1) has been well documented as an activator of citrus anthocyanin biosynthesis. In this study, we characterized CsMYB3, a transcriptional repressor that regulates anthocyanin biosynthesis in citrus. CsMYB3 was expressed in anthocyanin-pigmented tissues, and the expression was closely associated with that of Ruby1, which is a key anthocyanin activator. Overexpression of CsMYB3 in Arabidopsis resulted in a decrease in anthocyanins under nitrogen stress. Overexpression of CsMYB3 in the background of CsRuby1-overexpressing strawberry and Arabidopsis reduced the anthocyanin accumulation level. Transient promoter activation assays revealed that CsMYB3 could repress the activation capacity of the complex formed by CsRuby1/CsbHLH1 for the anthocyanin biosynthetic genes. Moreover, CsMYB3 could be transcriptionally activated by CsRuby1 via promoter binding, thus forming an ‘activator-and-repressor’ loop to regulate anthocyanin biosynthesis in citrus. This study shows that CsMYB3 plays a repressor role in the regulation of anthocyanin biosynthesis and proposes an ‘activator-and-repressor’ loop model constituted by CsRuby1 and CsMYB3 in the regulation of anthocyanin biosynthesis in citrus.

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