Genome sequence of the medicinal plant Tropaeolum majus provides insights into flavonoid biosynthesis

Abstract

Tropaeolum majus is a very popular species around the world with an enormous number of commercially available varieties displaying various flower color patterns and growth characteristics. It is rich in phytochemicals such as glucotropaeolin, hydroxycinnamic acid derivatives, and flavonol glycosides. Here, we report a highly continuous genome sequence of T. majus and a comprehensive annotation of protein encoding genes suitable for comparative genomics. The potential for the exploration of individual gene functions in this valuable plant is demonstrated by an analysis of the flavonoid biosynthesis genes and their transcriptional regulators. Important players of the flavonol biosynthesis, including structural genes and a transcription factor, were identified that are required to produce precursors of phytomedically relevant flavonol glycosides. The genome sequence does not reveal an ortholog of the leucoanthocyanidin reductase encoding gene (LAR), which aligns with previous reports about the absence of this gene in many Brassicales species.