title: Members of an R2R3-MYB transcription factor family in Petunia are developmentally and environmentally regulated to control complex floral and vegetative pigmentation patterning.
abstract: We present an investigation of anthocyanin regulation over the entire petunia plant, determining the mechanisms governing complex floral pigmentation patterning and environmentally induced vegetative anthocyanin synthesis. DEEP PURPLE (DPL) and PURPLE HAZE (PHZ) encode members of the R2R3-MYB transcription factor family that regulate anthocyanin synthesis in petunia, and control anthocyanin production in vegetative tissues and contribute to floral pigmentation. In addition to these two MYB factors, the basic helix-loop-helix (bHLH) factor ANTHOCYANIN1 (AN1) and WD-repeat protein AN11, are also essential for vegetative pigmentation. The induction of anthocyanins in vegetative tissues by high light was tightly correlated to the induction of transcripts for PHZ and AN1. Interestingly, transcripts for PhMYB27, a putative R2R3-MYB active repressor, were highly expressed during non-inductive shade conditions and repressed during high light. The competitive inhibitor PhMYBx (R3-MYB) was expressed under high light, which may provide feedback repression. In floral tissues DPL regulates vein-associated anthocyanin pigmentation in the flower tube, while PHZ determines light-induced anthocyanin accumulation on exposed petal surfaces (bud-blush). A model is presented suggesting how complex floral and vegetative pigmentation patterns are derived in petunia in terms of MYB, bHLH and WDR co-regulators.
authors.affiliation: New Zealand Institute for Plant and Food Research Limited, Private Bag 11-600, Palmerston North, New Zealand. nicholas.albert@plantandfood.co.nz
authors.forename: Nick W
authors.initials: NW
authors.lastname: Albert
authors.forename: David H
authors.initials: DH
authors.lastname: Lewis
authors.forename: Huaibi
authors.initials: H
authors.lastname: Zhang
authors.forename: Kathy E
authors.initials: KE
authors.lastname: Schwinn
authors.forename: Paula E
authors.initials: PE
authors.lastname: Jameson
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Davies
mesh_terms: D000483:Alleles; D000872:Anthocyanins / Q000096:biosynthesis*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008027:Light; D005810:Multigene Family; D032306:Petunia / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D018749:RNA, Plant / Q000235:genetics
chemical_list: D000872:Anthocyanins; D051792:Basic Helix-Loop-Helix Proteins; D010940:Plant Proteins; D018749:RNA, Plant; C106652:AN11 protein, Petunia x hybrida; C419702:anthocyanin1 protein, Petunia x hybrida