title: Anthocyanin biosynthesis regulation of DhMYB2 and DhbHLH1 in Dendrobium hybrids petals.
abstract: Dendrobium hybrids orchid are popular throughout the world. They have various floral color and pigmentation patterns that are mainly caused by anthocyanins. It is well established that anthocyanin biosynthesis is regulated by the interplay between MYB and bHLH transcription factors (TF) in most plants. In this study, we identified one R2R3-MYB gene, DhMYB2, and one bHLH gene, DhbHLH1, from a Dendrobium hybrid. Their expression profiles were related to anthocyanin pigmentation in Dendrobium petals. Transient over-expression of these two TF genes showed that both DhMYB2 and DhbHLH1 resulted in anthocyanin production in white petals. The interaction between the two TFs was observed in vitro. In different Dendrobium hybrids petals with various pigmentations, DhMYB2 and DhbHLH1 were co-expressed with DhDFR and DhANS, which are regarded as potential regulatory targets of the two TFs. In flowers with distinct purple lips but white or yellow petals/sepals, the expression of DhbHLH1 was only related to anthocyanin accumulation in the lips. Taken together, DhMYB2 interacted with DhbHLH1 to regulate anthocyanin production in Dendrobium hybrid petals. DhbHLH1 was also responsible for the distinct anthocyanin pigmentation in lip tissues. The functional characterization of DhMYB2 and DhbHLH1 will improve understanding of anthocyanin biosynthesis modulation in Dendrobium orchids.
authors.affiliation: Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou 571737, China; The Engineering Technology Research Center of Tropical Ornamental Plant Germplasm Innovation and Utilization, Hainan Province, Danzhou 571737, China.
authors.forename: Chonghui
authors.initials: C
authors.lastname: Li
authors.affiliation: Rubber Research Institute, CATAS/Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture, Danzhou 571737, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou 571737, China; Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Ding
authors.affiliation: Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou 571737, China; The Engineering Technology Research Center of Tropical Ornamental Plant Germplasm Innovation and Utilization, Hainan Province, Danzhou 571737, China.
authors.forename: Mingzhong
authors.initials: M
authors.lastname: Huang
authors.affiliation: Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou 571737, China; The Engineering Technology Research Center of Tropical Ornamental Plant Germplasm Innovation and Utilization, Hainan Province, Danzhou 571737, China.
authors.forename: Surong
authors.initials: S
authors.lastname: Huang
authors.affiliation: Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou 571737, China; The Engineering Technology Research Center of Tropical Ornamental Plant Germplasm Innovation and Utilization, Hainan Province, Danzhou 571737, China. Electronic address: 13976572870@163.com.
authors.forename: Guangsui
authors.initials: G
authors.lastname: Yang
authors.affiliation: Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou 571737, China; The Engineering Technology Research Center of Tropical Ornamental Plant Germplasm Innovation and Utilization, Hainan Province, Danzhou 571737, China. Electronic address: yinjunmei2011@sina.com.
authors.forename: Junmei
authors.initials: J
authors.lastname: Yin
mesh_terms: D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis*; D053898:Biosynthetic Pathways / Q000235:genetics; D016000:Cluster Analysis; D031667:Dendrobium / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006824:Hybridization, Genetic; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D020539:Sequence Analysis, Protein; D020798:Two-Hybrid System Techniques
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins
keywords: Anthocyanin pigmentation; R2R3-MYB; Transcription factor; Transcriptional regulation; bHLH