title: Molecular cloning and characterization of two genes encoding dihydroflavonol-4-reductase from Populus trichocarpa.
abstract: Dihydroflavonol 4-reductase (DFR, EC 1.1.1.219) is a rate-limited enzyme in the biosynthesis of anthocyanins and condensed tannins (proanthocyanidins) that catalyzes the reduction of dihydroflavonols to leucoanthocyanins. In this study, two full-length transcripts encoding for PtrDFR1 and PtrDFR2 were isolated from Populus trichocarpa. Sequence alignment of the two PtrDFRs with other known DFRs reveals the homology of these genes. The expression profile of PtrDFRs was investigated in various tissues of P. trichocarpa. To determine their functions, two PtrDFRs were overexpressed in tobacco (Nicotiana tabacum) via Agrobacterium-mediated transformation. The associated color change in the flowers was observed in all 35S:PtrDFR1 lines, but not in 35S:PtrDFR2 lines. Compared to the wild-type control, a significantly higher accumulation of anthocyanins was detected in transgenic plants harboring the PtrDFR1. Furthermore, overexpressing PtrDFR1 in Chinese white poplar (P. tomentosa Carr.) resulted in a higher accumulation of both anthocyanins and condensed tannins, whereas constitutively expressing PtrDFR2 only improved condensed tannin accumulation, indicating the potential regulation of condensed tannins by PtrDFR2 in the biosynthetic pathway in poplars.
authors.affiliation: Key Laboratory of Eco-Environments of Three Gorges Reservoir Region, Ministry of Education, Institute of Resources Botany, School of Life Sciences, Southwest University, Chongqing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Jiqing
authors.initials: J
authors.lastname: Gou
authors.forename: Zhichun
authors.initials: Z
authors.lastname: Jia
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Yimin
authors.initials: Y
authors.lastname: Sun
authors.forename: Xunyan
authors.initials: X
authors.lastname: Xiao
authors.forename: Feng
authors.initials: F
authors.lastname: Song
authors.forename: Keming
authors.initials: K
authors.lastname: Luo
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D035264:Flowers / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics; D030821:Plants, Genetically Modified; D032107:Populus / Q000201:enzymology* / Q000235:genetics*; D044945:Proanthocyanidins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014026:Nicotiana / Q000235:genetics
chemical_list: D000872:Anthocyanins; D044945:Proanthocyanidins; D012333:RNA, Messenger; D000429:Alcohol Oxidoreductases; C056570:dihydroflavanol 4-reductase