title: Maize Lc transcription factor enhances biosynthesis of anthocyanins, distinct proanthocyanidins and phenylpropanoids in apple (Malus domestica Borkh.).
abstract: Flavonoids are a large family of polyphenolic compounds with manifold functions in plants. Present in a wide range of vegetables and fruits, flavonoids form an integral part of the human diet and confer multiple health benefits. Here, we report on metabolic engineering of the flavonoid biosynthetic pathways in apple (Malus domestica Borkh.) by overexpression of the maize (Zea mays L.) leaf colour (Lc) regulatory gene. The Lc gene was transferred into the M. domestica cultivar Holsteiner Cox via Agrobacterium tumefaciens-mediated transformation which resulted in enhanced anthocyanin accumulation in regenerated shoots. Five independent Lc lines were investigated for integration of Lc into the plant genome by Southern blot and PCR analyses. The Lc-transgenic lines contained one or two Lc gene copies and showed increased mRNA levels for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), flavanone 3 beta-hydroxylase (FHT), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin reductases (LAR), anthocyanidin synthase (ANS) and anthocyanidin reductase (ANR). HPLC-DAD and LC-MS analyses revealed higher levels of the anthocyanin idaein (12-fold), the flavan 3-ol epicatechin (14-fold), and especially the isomeric catechin (41-fold), and some distinct dimeric proanthocyanidins (7 to 134-fold) in leaf tissues of Lc-transgenic lines. The levels of phenylpropanoids and their derivatives were only slightly increased. Thus, Lc overexpression in Malus domestica resulted in enhanced biosynthesis of specific flavonoid classes, which play important roles in both phytopathology and human health.
authors.affiliation: Institute of Biological Production Systems, Fruit Science Section, Leibniz University of Hannover, Herrenhaeuser Str. 2, 30419 Hannover, Germany.
authors.forename: Houhua
authors.initials: H
authors.lastname: Li
authors.forename: Henryk
authors.initials: H
authors.lastname: Flachowsky
authors.forename: Thilo C
authors.initials: TC
authors.lastname: Fischer
authors.forename: Magda-Viola
authors.initials: MV
authors.lastname: Hanke
authors.forename: Gert
authors.initials: G
authors.lastname: Forkmann
authors.forename: Dieter
authors.initials: D
authors.lastname: Treutter
authors.forename: Wilfried
authors.initials: W
authors.lastname: Schwab
authors.forename: Thomas
authors.initials: T
authors.lastname: Hoffmann
authors.forename: Iris
authors.initials: I
authors.lastname: Szankowski
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis*; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D018744:DNA, Plant; D027845:Malus / Q000378:metabolism*; D010666:Phenylpropionates / Q000378:metabolism*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry; D014157:Transcription Factors / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D017931:DNA Primers; D018744:DNA, Plant; D010666:Phenylpropionates; D014157:Transcription Factors