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

• Published in: PloS one Vol. 10; no. 11; p. e0143892
• Main Authors: Xiang, Li-li, Liu, Xiao-fen, Li, Xue, Yin, Xue-ren, Grierson, Donald, Li, Fang, Chen, Kun-song
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.11.2015; Public Library of Science (PLoS)
• Subjects: Analysis; Anthocyanins; Anthocyanins - biosynthesis; Arabidopsis; Basic Helix-Loop-Helix Transcription Factors - genetics; Basic Helix-Loop-Helix Transcription Factors - metabolism; Biology; Biosynthesis; Biotechnology; Chrysanthemum; Chrysanthemum - genetics; Chrysanthemum - metabolism; Chrysanthemum morifolium; Chrysanthemums; Cloning, Molecular - methods; College campuses; Cultivars; Enzymes; Flavonoids; Flowers; Flowers & plants; Flowers - chemistry; Gene Expression Regulation, Plant; Genes; Genes, Plant; Genomics; Helix-loop-helix proteins (basic); Horticulture; Laboratories; Multigene Family; Phylogeny; Physiological aspects; Pigments, Biological - genetics; Plant Proteins - genetics; Plant Proteins - metabolism; Promoter Regions, Genetic; Protein interaction; Protein-protein interactions; Regulators; Subgroups; Transcription factors; Two-Hybrid System Techniques; Yeast; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0143892

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.