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A Novel bHLH Transcription Factor Involved in Regulating Anthocyanin Biosynthesis in Chrysanthemums (Chrysanthemum morifolium Ramat.).

Xiang LL, Liu XF, Li X, Yin XR, Grierson D, Li F, Chen KS - PLoS ONE (2015)

Bottom Line: CmbHLH2 significantly upregulated the CmDFR promoter and triggered anthocyanin accumulation when co-expressed with CmMYB6.Yeast one-hybrid analyses indicated that CmbHLH2 was able to bind directly to the CmDFR promoter.These results suggest that CmbHLH2 is the essential partner for CmMYB6 in regulating anthocyanin biosynthesis in chrysanthemum.

View Article: PubMed Central - PubMed

Affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.

ABSTRACT
Chrysanthemums (Chrysanthemum morifolium Ramat.) exhibit a variety of flower colors due to their differing abilities to accumulate anthocyanins. One MYB member, CmMYB6, has been verified as a transcription regulator of chrysanthemum genes involved in anthocyanin biosynthesis; however, the co-regulators for CmMYB6 remain unclear in chrysanthemum. Here, the expression pattern of CmbHLH2, which is clustered in the IIIf bHLH subgroup, was shown to be positively correlated with the anthocyanin content of cultivars with red, pink and yellow flower colors, respectively. CmbHLH2 significantly upregulated the CmDFR promoter and triggered anthocyanin accumulation when co-expressed with CmMYB6. Yeast one-hybrid analyses indicated that CmbHLH2 was able to bind directly to the CmDFR promoter. Moreover, yeast two-hybrid assays indicated protein-protein interaction between CmbHLH2 and CmMYB6. These results suggest that CmbHLH2 is the essential partner for CmMYB6 in regulating anthocyanin biosynthesis in chrysanthemum.

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In vivo interactions between CmMYB6, CmbHLHs and the CmDFR promoter were revealed by dual luciferase assays in tobacco leaves.Error bars are the S.E. of three independent experiments with at least four replicates.
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pone.0143892.g004: In vivo interactions between CmMYB6, CmbHLHs and the CmDFR promoter were revealed by dual luciferase assays in tobacco leaves.Error bars are the S.E. of three independent experiments with at least four replicates.

Mentions: To predict the transcriptional regulating roles of CmbHLH1 and CmbHLH2, dual luciferase assay with the CmDFR promoter were used in this study. Based on the results, CmbHLH1 or CmbHLH2 singly had no effect on the activity of CmDFR promoter compared to the empty vector, activity of which was set as one, whereas CmMYB6 induced an approximately 8-fold increase in CmDFR promoter activity (Fig 4). However, when co-expressed with CmMYB6, CmbHLH2 showed a significant synergistic effect and CmDFR promoter activity was stimulated over 40-fold (Fig 4). CmbHLH1, on the other hand, was unable to up-regulate the activity of CmDFR promoter when co-expressed either with empty vector or with CmMYB6 (Fig 4). This indicated that CmbHLH2, but not CmbHLH1, has the ability to regulate anthocyanin biosynthesis.


A Novel bHLH Transcription Factor Involved in Regulating Anthocyanin Biosynthesis in Chrysanthemums (Chrysanthemum morifolium Ramat.).

Xiang LL, Liu XF, Li X, Yin XR, Grierson D, Li F, Chen KS - PLoS ONE (2015)

In vivo interactions between CmMYB6, CmbHLHs and the CmDFR promoter were revealed by dual luciferase assays in tobacco leaves.Error bars are the S.E. of three independent experiments with at least four replicates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664390&req=5

pone.0143892.g004: In vivo interactions between CmMYB6, CmbHLHs and the CmDFR promoter were revealed by dual luciferase assays in tobacco leaves.Error bars are the S.E. of three independent experiments with at least four replicates.
Mentions: To predict the transcriptional regulating roles of CmbHLH1 and CmbHLH2, dual luciferase assay with the CmDFR promoter were used in this study. Based on the results, CmbHLH1 or CmbHLH2 singly had no effect on the activity of CmDFR promoter compared to the empty vector, activity of which was set as one, whereas CmMYB6 induced an approximately 8-fold increase in CmDFR promoter activity (Fig 4). However, when co-expressed with CmMYB6, CmbHLH2 showed a significant synergistic effect and CmDFR promoter activity was stimulated over 40-fold (Fig 4). CmbHLH1, on the other hand, was unable to up-regulate the activity of CmDFR promoter when co-expressed either with empty vector or with CmMYB6 (Fig 4). This indicated that CmbHLH2, but not CmbHLH1, has the ability to regulate anthocyanin biosynthesis.

Bottom Line: CmbHLH2 significantly upregulated the CmDFR promoter and triggered anthocyanin accumulation when co-expressed with CmMYB6.Yeast one-hybrid analyses indicated that CmbHLH2 was able to bind directly to the CmDFR promoter.These results suggest that CmbHLH2 is the essential partner for CmMYB6 in regulating anthocyanin biosynthesis in chrysanthemum.

View Article: PubMed Central - PubMed

Affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.

ABSTRACT
Chrysanthemums (Chrysanthemum morifolium Ramat.) exhibit a variety of flower colors due to their differing abilities to accumulate anthocyanins. One MYB member, CmMYB6, has been verified as a transcription regulator of chrysanthemum genes involved in anthocyanin biosynthesis; however, the co-regulators for CmMYB6 remain unclear in chrysanthemum. Here, the expression pattern of CmbHLH2, which is clustered in the IIIf bHLH subgroup, was shown to be positively correlated with the anthocyanin content of cultivars with red, pink and yellow flower colors, respectively. CmbHLH2 significantly upregulated the CmDFR promoter and triggered anthocyanin accumulation when co-expressed with CmMYB6. Yeast one-hybrid analyses indicated that CmbHLH2 was able to bind directly to the CmDFR promoter. Moreover, yeast two-hybrid assays indicated protein-protein interaction between CmbHLH2 and CmMYB6. These results suggest that CmbHLH2 is the essential partner for CmMYB6 in regulating anthocyanin biosynthesis in chrysanthemum.

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