title: Expression analysis of anthocyanin regulatory genes in response to different light qualities in Arabidopsis thaliana.
abstract: In this work we analysed, at the transcript level, the response of Arabidopsis anthocyanin regulatory genes of the MYB (PAP1 and PAP2), bHLH (TT8, EGL3 and GL3) and WD40 (TTG1) families to white light in seedlings and to different light qualities in rosette leaves. Our experiments showed strong light induction of the MYB genes PAP1 and PAP2. In particular, the kinetics of PAP1 expression preceded those of PAP2 and all of the structural genes (CHS, DFR, F3H, LDOX), consistent with the hypothesis that it has a key role in light induction of anthocyanin biosynthesis. All bHLH genes analysed showed light induction, and in seedlings their expression preceded that of the late structural genes, suggesting their possible role in light regulation of these structural genes. TTG1 expression is essentially constitutive in both systems. Experiments with transgenic lines over-expressing the MYB factors show that PAP1, but not PAP2, strongly stimulates expression of the anthocyanin structural gene encoding dihydroflavonol reductase, but neither factor affected expression of the early flavonoid biosynthesis gene encoding chalcone synthase. Consistent with these findings, PAP1, but not PAP2, stimulated light induction of anthocyanin biosynthesis in seedlings. We conclude that specific members of the MYB and bHLH families play important roles in regulating anthocyanin biosynthesis in response to different light qualities in Arabidopsis.
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Via Celoria, 26, 20133 Milano, Italy. eleonora.cominelli@unimi.it
authors.forename: Eleonora
authors.initials: E
authors.lastname: Cominelli
authors.forename: Giuliana
authors.initials: G
authors.lastname: Gusmaroli
authors.forename: Domenico
authors.initials: D
authors.lastname: Allegra
authors.forename: Massimo
authors.initials: M
authors.lastname: Galbiati
authors.forename: Helena K
authors.initials: HK
authors.lastname: Wade
authors.forename: Gareth I
authors.initials: GI
authors.lastname: Jenkins
authors.forename: Chiara
authors.initials: C
authors.lastname: Tonelli
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics* / Q000528:radiation effects*; D029681:Arabidopsis Proteins; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D017343:Genes, Plant; D005809:Genes, Regulator; D008027:Light; D000073718:Pancreatitis-Associated Proteins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000235:genetics / Q000528:radiation effects; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; D000073718:Pancreatitis-Associated Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C502612:AT1G56650 protein, Arabidopsis; C514560:PAP2 protein, Arabidopsis; C000612141:REG3A protein, human