title: Negative regulation of anthocyanin biosynthesis in Arabidopsis by a miR156-targeted SPL transcription factor.
abstract: Flavonoids are synthesized through an important metabolic pathway that leads to the production of diverse secondary metabolites, including anthocyanins, flavonols, flavones, and proanthocyanidins. Anthocyanins and flavonols are derived from Phe and share common precursors, dihydroflavonols, which are substrates for both flavonol synthase and dihydroflavonol 4-reductase. In the stems of Arabidopsis thaliana, anthocyanins accumulate in an acropetal manner, with the highest level at the junction between rosette and stem. We show here that this accumulation pattern is under the regulation of miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, which are deeply conserved and known to have important roles in regulating phase change and flowering. Increased miR156 activity promotes accumulation of anthocyanins, whereas reduced miR156 activity results in high levels of flavonols. We further provide evidence that at least one of the miR156 targets, SPL9, negatively regulates anthocyanin accumulation by directly preventing expression of anthocyanin biosynthetic genes through destabilization of a MYB-bHLH-WD40 transcriptional activation complex. Our results reveal a direct link between the transition to flowering and secondary metabolism and provide a potential target for manipulation of anthocyanin and flavonol content in plants.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: Jin-Ying
authors.initials: JY
authors.lastname: Gou
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Felippes
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Liu
authors.forename: Detlef
authors.initials: D
authors.lastname: Weigel
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Wang
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000872:Anthocyanins / Q000096:biosynthesis* / Q000737:chemistry; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002853:Chromatography, Liquid; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D013058:Mass Spectrometry; D035683:MicroRNAs / Q000378:metabolism*; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; D035683:MicroRNAs; C559759:Mirn156 microRNA, Arabidopsis; D046912:Multiprotein Complexes; C531404:SPL9 protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors; D000429:Alcohol Oxidoreductases; C056570:dihydroflavanol 4-reductase