Ectopic expression of snapdragon transcription factors facilitates the identification of genes encoding enzymes of anthocyanin decoration in tomato

Takayuki Tohge, Yang Zhang, Silke Peterek, Andrea Matros, Ghanasyam Rallapalli, Yudelsy A. Tandrón, Eugenio Butelli, Kalyani Kallam, Norbert Hertkorn, Hans-Peter Mock, Cathie Martin, Alisdair R. Fernie

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Given the potential health benefits of polyphenolic compounds in the diet, there is a growing interest in the generation of food crops enriched with health-protective flavonoids. We undertook a series of metabolite analyses of tomatoes ectopically expressing the Delila and Rosea1 transcription factor genes from snapdragon (Antirrhinum majus), paying particular attention to changes in phenylpropanoids compared to controls. These analyses revealed multiple changes, including depletion of rutin and naringenin chalcone, and enhanced levels of anthocyanins and phenylacylated flavonol derivatives. We isolated and characterized the chemical structures of the two most abundant anthocyanins, which were shown by NMR spectroscopy to be delphinidin-3-(4'''-O-trans-p-coumaroyl)-rutinoside-5-O-glucoside and petunidin-3-(4'''-O-trans-p-coumaroyl)-rutinoside-5-O-glucoside. By performing RNA sequencing on both purple fruit and wild-type fruit, we obtained important information concerning the relative expression of both structural and transcription factor genes. Integrative analysis of the transcript and metabolite datasets provided compelling evidence of the nature of all anthocyanin biosynthetic genes, including those encoding species-specific anthocyanin decoration enzymes. One gene, SlFdAT1 (Solyc12g088170), predicted to encode a flavonoid-3-O-rutinoside-4'''-phenylacyltransferase, was characterized by assays of recombinant protein and over-expression assays in tobacco. The combined data are discussed in the context of both our current understanding of phenylpropanoid metabolism in Solanaceous species, and evolution of flavonoid decorating enzymes and their transcriptional networks in various plant species.

Original languageEnglish
Pages (from-to)686-704
Number of pages19
JournalThe Plant Journal
Volume83
Issue number4
Early online date8 Aug 2015
DOIs
Publication statusPublished - Aug 2015

Keywords

  • anthocyanin metabolism
  • tomato
  • Solanaceous species
  • RNA-seq
  • acyltransferase
  • glycosyltransferase

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