Limits...
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.

Show MeSH
Transient over-expression of CmMYB6 and CmbHLH1 or CmbHLH2 carried out in tobacco leaves.(a) Photographs taken 8 days after the infiltration. (b) Analysis of anthocyanin contents of tobacco leaves 8 days after infiltration with the TFs. Each experiment was carried out with three biological repeats and the error bars represent the S.E. of these replicate reactions.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4664390&req=5

pone.0143892.g007: Transient over-expression of CmMYB6 and CmbHLH1 or CmbHLH2 carried out in tobacco leaves.(a) Photographs taken 8 days after the infiltration. (b) Analysis of anthocyanin contents of tobacco leaves 8 days after infiltration with the TFs. Each experiment was carried out with three biological repeats and the error bars represent the S.E. of these replicate reactions.

Mentions: To confirm the role of CmbHLH2 in the regulation of anthocyanin biosynthesis, a transient expression assay was performed in tobacco leaves. Although CmMYB6 could stimulate the activity of the CmDFR promoter (Fig 4), anthocyanin accumulation could not be triggered by a single CmMYB6 member (S3 Fig). Similarly, CmbHLH1 or CmbHLH2 singly could not regulate anthocyanin biosynthesis in tobacco leaves (Fig 7). Only the patches infiltrated with both CmMYB6 and CmbHLH2 had the ability to produce a dramatic accumulation of anthocyanin, of up to 5.0 mg/gFW on the 8th day after infiltration (Fig 7). Based on these results, CmbHLH2 is the crucial and essential member of the MBW transcription complex regulating anthocyanin biosynthesis together with CmMYB6 in chrysanthemum.


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)

Transient over-expression of CmMYB6 and CmbHLH1 or CmbHLH2 carried out in tobacco leaves.(a) Photographs taken 8 days after the infiltration. (b) Analysis of anthocyanin contents of tobacco leaves 8 days after infiltration with the TFs. Each experiment was carried out with three biological repeats and the error bars represent the S.E. of these replicate reactions.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0143892.g007: Transient over-expression of CmMYB6 and CmbHLH1 or CmbHLH2 carried out in tobacco leaves.(a) Photographs taken 8 days after the infiltration. (b) Analysis of anthocyanin contents of tobacco leaves 8 days after infiltration with the TFs. Each experiment was carried out with three biological repeats and the error bars represent the S.E. of these replicate reactions.
Mentions: To confirm the role of CmbHLH2 in the regulation of anthocyanin biosynthesis, a transient expression assay was performed in tobacco leaves. Although CmMYB6 could stimulate the activity of the CmDFR promoter (Fig 4), anthocyanin accumulation could not be triggered by a single CmMYB6 member (S3 Fig). Similarly, CmbHLH1 or CmbHLH2 singly could not regulate anthocyanin biosynthesis in tobacco leaves (Fig 7). Only the patches infiltrated with both CmMYB6 and CmbHLH2 had the ability to produce a dramatic accumulation of anthocyanin, of up to 5.0 mg/gFW on the 8th day after infiltration (Fig 7). Based on these results, CmbHLH2 is the crucial and essential member of the MBW transcription complex regulating anthocyanin biosynthesis together with CmMYB6 in chrysanthemum.

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.

Show MeSH