The Purple Cauliflower Arises from Activation of a MYB Transcription Factor.

The Purple Cauliflower Arises from Activation of a MYB Transcription Factor.: "Publication Date: 2010 Sep 20 PMID: 20855520
Authors: Chiu, L. W. - Zhou, X. - Burke, S. - Wu, X. - Prior, R. - Li, L.
Journal: Plant Physiol

Anthocyanins are responsible for the color of many flowers, fruits, and vegetables. An interesting and unique Purple (Pr) gene mutation in cauliflower confers an abnormal pattern of anthocyanin accumulation, giving the striking mutant phenotype of intense purple color in curds and a few other tissues. To unravel the nature of the Pr mutation in cauliflower, we isolated the Pr gene via a combination of candidate gene analysis and fine-mapping. Pr encoded a R2R3 MYB transcription factor that exhibited tissue-specific expression, consistent with an abnormal anthocyanin accumulation pattern in the mutant. Transgenic Arabidopsis and cauliflower plants expressing the Pr-D allele recapitulated the mutant phenotype, confirming the isolation of the Pr gene. Up-regulation of Pr specifically activated a bHLH transcription factor and a subset of anthocyanin structural genes (BoF3'H, BoDFR, and BoLDOX ) to confer ectopic accumulation of pigments in the purple cauliflower. Our results indicate that the genetic variation including a Harbinger DNA transposon insertion in the upstream regulatory region of the Pr-D allele is responsible for the up-regulation of the Pr gene in inducing phenotypic change in the plant. The successful isolation of Pr provides important information on the regulatory control of anthocyanin biosynthesis in Brassica vegetables, and offers a genetic resource for development of new varieties with enhanced health-promoting properties and visual appeal.

(Via Plant Physiology.)