Genome sequence of the medicinal and ornamental plantDigitalis purpureareveals the molecular basis of flower color variation

Digitalis purpurea (foxglove) is a widely distributed ornamental plant and the producer of the biomedical compound digoxin. Here, we present a long read sequencing-based genome sequence of a red flowering D. purpurea plant and a corresponding prediction of gene models. The high assembly continuity is indicated by the N50 of 4.3 Mbp and the completeness is supported by discovery of about 96% complete BUSCO genes. This genomic resource paves the way for an in-depth investigation of the flower pigmentation of D. purpurea . Structural genes of the anthocyanin biosynthesis and the corresponding transcriptional regulators were identified. The comparison of red and white flowering plants revealed a large insertion in the anthocyanidin synthase gene in white flowering plants that most likely renders this gene non-functional and could explain the loss of anthocyanin pigmentation. In addition, the anthocyanin biosynthesis activator MYB5 shows a 18 bp deletion in white flowering plants that results in the loss of 6 amino acids in the protein. Furthermore, we found a large insertion in the DpTFL1/CEN gene to be responsible for the development of large terminal flowers.