title: Disequilibrium of Flavonol Synthase and Dihydroflavonol-4-Reductase Expression Associated Tightly to White vs. Red Color Flower Formation in Plants.
abstract: Flower color is the main character throughout the plant kingdom. Though substantial information exists regarding the structural and regulatory genes involved in anthocyanin and flavonol biosynthesis, little is known that what make a diverse white vs. red color flower in natural species. Here, the contents of pigments in seven species from varied phylogenetic location in plants with red and white flowers were determined. Flavonols could be detected in red and white flowers, but anthocyanins were almost undetectable in the white cultivar. Comparisons of expression patterns of gene related to the flavonoid biosynthesis indicated that disequilibrium expression of flavonol synthase (FLS) and dihydroflavonol-4-reductase (DFR) genes determined the accumulation of flavonols and anothcyanins in both red and white flowers of seven species. To further investigate the role of such common regulatory patterns in determining flower color, FLS genes were isolated from Rosa rugosa (RrFLS1), Prunus persica (PpFLS), and Petunia hybrida (PhFLS), and DFR genes were isolated from Rosa rugosa (RrDFR1) and Petunia hybrida (PhDFR). Heterologous expression of the FLS genes within tobacco host plants demonstrated conservation of function, with the transgenes promoting flavonol biosynthesis and inhibiting anthocyanin accumulation, so resulting in white flowers. Conversely, overexpression of DFR genes in tobacco displayed down-regulation of the endogenous NtFLS gene, and the promotion of anthocyanin synthesis. On this basis, we propose a model in which FLS and DFR gene-products compete for common substrates in order to direct the biosynthesis of flavonols and anthocyanins, respectively, thereby determining white vs. red coloration of flowers.
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Luo
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.
authors.forename: Guogui
authors.initials: G
authors.lastname: Ning
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.
authors.forename: Yuxiao
authors.initials: Y
authors.lastname: Shen
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China.
authors.forename: Huanan
authors.initials: H
authors.lastname: Jin
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China.
authors.forename: Penghui
authors.initials: P
authors.lastname: Li
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Huang
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.
authors.forename: Manzhu
authors.initials: M
authors.lastname: Bao
keywords: DFR; FLS; anthocyanins; disequilibrium; flavonols; flower color