title: Engineering of the rose flavonoid biosynthetic pathway successfully generated blue-hued flowers accumulating delphinidin.
abstract: Flower color is mainly determined by anthocyanins. Rosa hybrida lacks violet to blue flower varieties due to the absence of delphinidin-based anthocyanins, usually the major constituents of violet and blue flowers, because roses do not possess flavonoid 3',5'-hydoxylase (F3'5'H), a key enzyme for delphinidin biosynthesis. Other factors such as the presence of co-pigments and the vacuolar pH also affect flower color. We analyzed the flavonoid composition of hundreds of rose cultivars and measured the pH of their petal juice in order to select hosts of genetic transformation that would be suitable for the exclusive accumulation of delphinidin and the resulting color change toward blue. Expression of the viola F3'5'H gene in some of the selected cultivars resulted in the accumulation of a high percentage of delphinidin (up to 95%) and a novel bluish flower color. For more exclusive and dominant accumulation of delphinidin irrespective of the hosts, we down-regulated the endogenous dihydroflavonol 4-reductase (DFR) gene and overexpressed the Irisxhollandica DFR gene in addition to the viola F3'5'H gene in a rose cultivar. The resultant roses exclusively accumulated delphinidin in the petals, and the flowers had blue hues not achieved by hybridization breeding. Moreover, the ability for exclusive accumulation of delphinidin was inherited by the next generations.
authors.affiliation: Suntory Limited Research Center, Institute for Plant Science, 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka, 618-8503 Japan. Yoshikazu_Tanaka@suntory.co.jp
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Katsumoto
authors.forename: Masako
authors.initials: M
authors.lastname: Fukuchi-Mizutani
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fukui
authors.forename: Filippa
authors.initials: F
authors.lastname: Brugliera
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Holton
authors.forename: Mirko
authors.initials: M
authors.lastname: Karan
authors.forename: Noriko
authors.initials: N
authors.lastname: Nakamura
authors.forename: Keiko
authors.initials: K
authors.lastname: Yonekura-Sakakibara
authors.forename: Junichi
authors.initials: J
authors.lastname: Togami
authors.forename: Alix
authors.initials: A
authors.lastname: Pigeaire
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Tao
authors.forename: Narender S
authors.initials: NS
authors.lastname: Nehra
authors.forename: Chin-Yi
authors.initials: CY
authors.lastname: Lu
authors.forename: Barry K
authors.initials: BK
authors.lastname: Dyson
authors.forename: Shinzo
authors.initials: S
authors.lastname: Tsuda
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ashikari
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kusumi
authors.forename: John G
authors.initials: JG
authors.lastname: Mason
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000872:Anthocyanins / Q000737:chemistry / Q000378:metabolism*; D005419:Flavonoids / Q000096:biosynthesis* / Q000737:chemistry; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D010641:Phenotype; D010860:Pigments, Biological / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D027826:Rosa / Q000235:genetics / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010860:Pigments, Biological; D010940:Plant Proteins; D000429:Alcohol Oxidoreductases; C056570:dihydroflavanol 4-reductase; C017185:delphinidin