title: Identification and characterization of MYB-bHLH-WD40 regulatory complexes controlling proanthocyanidin biosynthesis in strawberry (Fragaria × ananassa) fruits.
abstract: Strawberry (Fragaria × ananassa) fruits contain high concentrations of flavonoids. In unripe strawberries, the flavonoids are mainly represented by proanthocyanidins (PAs), while in ripe fruits the red-coloured anthocyanins also accumulate. Most of the structural genes leading to PA biosynthesis in strawberry have been characterized, but no information is available on their transcriptional regulation. In Arabidopsis thaliana the expression of the PA biosynthetic genes is specifically induced by a ternary protein complex, composed of AtTT2 (AtMYB123), AtTT8 (AtbHLH042) and AtTTG1 (WD40-repeat protein). A strategy combining yeast-two-hybrid screening and agglomerative hierarchical clustering of transcriptomic and metabolomic data was undertaken to identify strawberry PA regulators. Among the candidate genes isolated, four were similar to AtTT2, AtTT8 and AtTTG1 (FaMYB9/FaMYB11, FabHLH3 and FaTTG1, respectively) and two encode putative negative regulators (FaMYB5 and FabHLH3∆). Interestingly, FaMYB9/FaMYB11, FabHLH3 and FaTTG1 were found to complement the tt2-1, tt8-3 and ttg1-1 transparent testa mutants, respectively. In addition, they interacted in yeast and activated the Arabidopsis BANYULS (anthocyanidin reductase) gene promoter when coexpressed in Physcomitrella patens protoplasts. Taken together, these results demonstrated that FaMYB9/FaMYB11, FabHLH3 and FaTTG1 are the respective functional homologues of AtTT2, AtTT8 and AtTTG1, providing new tools for modifying PA content and strawberry fruit quality.
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, the Netherlands.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Schaart
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.|AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Dubos
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, the Netherlands.
authors.forename: Irene
authors.initials: I
authors.lastname: Romero De La Fuente
authors.affiliation: Plant Research International, Business Unit Bioscience, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, the Netherlands.
authors.forename: Adèle M M L
authors.initials: AMML
authors.lastname: van Houwelingen
authors.affiliation: Plant Research International, Business Unit Bioscience, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, the Netherlands.|Centre for Biosystems Genomics, PO Box 98, 6700 AB, Wageningen, the Netherlands.
authors.forename: Ric C H
authors.initials: RCH
authors.lastname: de Vos
authors.affiliation: Plant Research International, Business Unit Bioscience, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, the Netherlands.|Centre for Biosystems Genomics, PO Box 98, 6700 AB, Wageningen, the Netherlands.
authors.forename: Harry H
authors.initials: HH
authors.lastname: Jonker
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.|AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Xu
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.|AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Routaboul
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.|AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78026, Versailles, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Lepiniec
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, the Netherlands.|Centre for Biosystems Genomics, PO Box 98, 6700 AB, Wageningen, the Netherlands.
authors.forename: Arnaud G
authors.initials: AG
authors.lastname: Bovy
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D019068:Bryopsida / Q000378:metabolism; D016000:Cluster Analysis; D003433:Crosses, Genetic; D044948:Flavonols / Q000378:metabolism; D031985:Fragaria / Q000235:genetics* / Q000254:growth & development; D005638:Fruit / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test; D055442:Metabolome / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D044945:Proanthocyanidins / Q000096:biosynthesis*; D011523:Protoplasts / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D059467:Transcriptome / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D044948:Flavonols; D010940:Plant Proteins; D044945:Proanthocyanidins; C013221:proanthocyanidin