title: Related allopolyploids display distinct floral pigment profiles and transgressive pigments.
abstract: OBJECTIVE
  Both polyploidy and shifts in floral color have marked angiosperm evolution. Here, we investigate the biochemical basis of the novel and diverse floral phenotypes seen in allopolyploids in Nicotiana (Solanaceae) and examine the extent to which the merging of distinct genomes alters flavonoid pigment production.
  
  
  METHODS
  We analyzed flavonol and anthocyanin pigments from Nicotiana allopolyploids of different ages (N. tabacum, 0.2 million years old; several species from Nicotiana section Repandae, 4.5 million years old; and five lines of first-generation synthetic N. tabacum) as well as their diploid progenitors.
  
  
  RESULTS
  Allopolyploid floral pigment profiles tend not to overlap with their progenitors or related allopolyploids, and allopolyploids produce transgressive pigments that are not present in either progenitor. Differences in floral color among N. tabacum accessions seems mainly to be due to variation in cyanidin concentration, but changes in flavonol concentrations among accessions are also present.
  
  
  CONCLUSIONS
  Competition for substrates within the flavonoid biosynthetic pathway to make either flavonols or anthocyanins may drive the differences seen among related allopolyploids. Some of the pigment differences observed in allopolyploids may be associated with making flowers more visible to nocturnal pollinators.
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, 2109 Batchelor Hall, Riverside, California 92521 USA.
authors.forename: Elizabeth W
authors.initials: EW
authors.lastname: McCarthy
authors.affiliation: University of Colorado, Boulder, C127 Ramaley Hall, Campus Box 334, Boulder, Colorado 80309 USA.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Berardi
authors.affiliation: University of Colorado, Boulder, C127 Ramaley Hall, Campus Box 334, Boulder, Colorado 80309 USA.
authors.forename: Stacey D
authors.initials: SD
authors.lastname: Smith
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, 2109 Batchelor Hall, Riverside, California 92521 USA amy.litt@ucr.edu.
authors.forename: Amy
authors.initials: A
authors.lastname: Litt
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics; D003116:Color; D005419:Flavonoids / Q000378:metabolism; D035264:Flowers / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics*; D010860:Pigments, Biological / Q000378:metabolism; D011123:Polyploidy; D013045:Species Specificity; D014026:Nicotiana / Q000145:classification / Q000235:genetics* / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010860:Pigments, Biological; C017154:cyanidin
keywords: Nicotiana; allopolyploidy; anthocyanin; evolution; flavonol; flower color; transgressive characters