Regulatory Genes Controlling Anthocyanin Pigmentation Are Functionally Conserved among Plant Species and Have Distinct Sets of Target Genes (original) (raw)

In this study, we demonstrate that in petunia at least four regulatory genes (anthocyanin-7 [anl], an2, an4, and an77) control transcription of a subset of structural genes from the anthocyanin pathway by using a combination of RNA gel blot analysis, transcription run-on assays, and transient expression assays. an2and an77-mutants could be transiently complemented by the maize regulatory genes Leaf color (Lc) or Colorless-7 (CT), respectively, whereas anímutants only by Lc and C7 together. In addition, the combination of Lc and C7 induces pigment accumulation in young leaves. This indicates that Lc and C7 are both necessary and sufficient to produce pigmentation in leaf cells. Regulatory pigmentation genes in maize and petunia control different sets of structural genes. The maize Lc and C7 genes expressed in petunia differentially activate the promoters of the chalcone synthase genes chsA and chsJ in the same way that the homologous petunia genes do. This suggests that the regulatory proteins in both species are functionally similar and that the choice of target genes is determined by their promoter sequences. We present an evolutionary model that explains the differences in regulation of pigmentation pathways of maize, petunia, and snapdragon.