title: An R2R3-MYB transcription factor regulates carotenoid pigmentation in Mimulus lewisii flowers.
abstract: Carotenoids are yellow, orange, and red pigments that contribute to the beautiful colors and nutritive value of many flowers and fruits. The structural genes in the highly conserved carotenoid biosynthetic pathway have been well characterized in multiple plant systems, but little is known about the transcription factors that control the expression of these structural genes. By analyzing a chemically induced mutant of Mimulus lewisii through bulk segregant analysis and transgenic experiments, we have identified an R2R3-MYB, Reduced Carotenoid Pigmentation 1 (RCP1), as the first transcription factor that positively regulates carotenoid biosynthesis during flower development. Loss-of-function mutations in RCP1 lead to down-regulation of all carotenoid biosynthetic genes and reduced carotenoid content in M. lewisii flowers, a phenotype recapitulated by RNA interference in the wild-type background. Overexpression of this gene in the rcp1 mutant background restores carotenoid production and, unexpectedly, results in simultaneous decrease of anthocyanin production in some transgenic lines by down-regulating the expression of an activator of anthocyanin biosynthesis. Identification of transcriptional regulators of carotenoid biosynthesis provides the 'toolbox' genes for understanding the molecular basis of flower color diversification in nature and for potential enhancement of carotenoid production in crop plants via genetic engineering.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Janelle M
authors.initials: JM
authors.lastname: Sagawa
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Stanley
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Amy M
authors.initials: AM
authors.lastname: LaFountain
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Harry A
authors.initials: HA
authors.lastname: Frank
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.|Institute for Systems Genomics, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Yao-Wu
authors.initials: YW
authors.lastname: Yuan
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis; D053898:Biosynthetic Pathways / Q000235:genetics; D002338:Carotenoids / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics; D035264:Flowers / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D056726:Genetic Association Studies; D032241:Mimulus / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010858:Pigmentation / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins; D014157:Transcription Factors; D002338:Carotenoids
keywords: MYB transcription factor; carotenoid biosynthesis; flower color; monkeyflowers (Mimulus); pigmentation