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ARS Home » Research » Publications at this Location » Publication #223869
Title: Differential Expression of Transcription Factors Associated With Anthocyanin Pigmentation in Capsicum

Author
item LIGHTBOURN, GORDON - VA POLYTECH INST/UNIV
item WINKEL, BRENDA - VA POLYTECH INST/UNIV
item Griesbach, Robert
item Stommel, John

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 3/28/2008
Publication Date: 7/1/2008
Citation: Lightbourn, G., Winkel, B., Griesbach, R.J., Stommel, J.R. 2008. Differential Expression of Transcription Factors Associated With Anthocyanin Pigmentation in Capsicum. HortScience.

Interpretive Summary:

Technical Abstract: Anthocyanin structural gene transcription requires the expression of at least one of each of three transcription factor families- MYC, MYB and WD40. These transcription factors form a complex that binds to structural gene promoters, thus modulating gene expression. Capsicum displays a wide spectrum of tissue-specific anthocyanin pigmentation making it a model plant for study of anthocyanin accumulation. In order to determine the genetic basis for tissue-specific pigmentation, we evaluated anthocyanin related structural (Chs, Dfr, Ans) and regulatory (Myc, Myb, WD40) gene expression in flower, fruit and foliar tissue from genotypes that displayed differential anthocyanin accumulation. In all tissue types, structural gene transcript levels were significantly higher in anthocyanin pigmented tissue in comparison to non-pigmented tissues. Myb and Myc transcript levels were also significantly greater in anthocyanin pigmented fruit and floral tissues. Differential expression of Myb and Myc was not observed in leaf tissue suggesting that additional mechanisms contribute to regulation of anthocyanin-related structural genes in foliar tissue. Differential expression of WD40 was not observed in any tissue. Sequence analysis of anthocyanin pigmented tissues revealed a family of anthocyanin related Myb genes differing in intron number. A single uninterrupted transcript was expressed in anthocyanin pigmented tissues. An analogous transcript was not present in non-pigmented tissue. Sequence analysis of Myc cDNA derived from anthocyanin pigmented tissue revealed two transcripts with identical ORFs but divergent untranslated terminal 3’regions. Similar to Myb, comparison of genomic sequence from anthocyanin pigmented and non-pigmented tissue revealed a family of Myc genes associated with anthocyanin structural gene expression and pigment accumulation.