Jakob Maximilian Horz

Digitalis purpurea (foxglove) is a widely distributed ornamental plant. Here, we present a long read sequencing-based genome sequence of a magenta 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 magenta 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. Furthermore, we found a large insertion in the DpTFL1/CEN gene to be likely responsible for the development of large terminal flowers.

While most plant lineages are pigmented by anthocyanins, several families in the Caryophyllales represent a major exception by showing a replacement of anthocyanin pigmentation by betalain pigmentation. The mutual exclusion of anthocyanins and betalains at the family level has been well established for over 50 years and has been mechanistically explained. Chenopodiaceae are a betalain-pigmented lineage lacking a key anthocyanin biosynthesis gene and lacking the key activating transcription factor of the anthocyanin biosynthesis. A publication by Zhang et al., 2024 claims that anthocyanins would be responsible for the red pigmentation in leaves of Chenopodium quinoa . Here, we assessed this study and reanalyzed the RNA-seq datasets generated in this study to demonstrate that there is no evidence for anthocyanin biosynthesis, but activity of the betalain and carotenoid biosynthesis could explain the observed pigmentation of quinoa leaves.

Anthocyanins are well known as colorants of flowers, but many other invisible functions might have been more important during the evolution of complex biosynthesis networks in plants. The number of anthocyanin decorating enzymes, the subtle control of structural genes by numerous transcription factors, and routes of intracellular anthocyanin transport are reviewed here. Various ecological functions of anthocyanins hold the key to understanding evolutionary trajectories that lead to the success of these pigments. Proposed functions include carbon sinks that prevent excessive sugar levels, sun blockers protecting the photosynthesis apparatus, antioxidants scavenging reactive oxygen species, providing camouflage, and attraction of pollinators and seed dispersers. Anthocyanins clearly fulfill different functions in different plant organs. It is currently believed that protective functions in leaves gave rise to the biosynthesis network and that flower and fruit coloration evolved later. Despite decades of research on the anthocyanin biosynthesis, there is still substantial potential for fundamental discoveries.

Anthocyanins are well known as colorants of flowers, but many other invisible functions might have been more important during the evolution of complex biosynthesis networks in plants. The number of anthocyanin decorating enzymes, the subtle control of structural genes by numerous transcription factors, and routes of intracellular anthocyanin transport are reviewed here. Various ecological functions of anthocyanins hold the key to understanding evolutionary trajectories that lead to the success of these pigments. Proposed functions include carbon sinks that prevent excessive sugar levels, sun blockers protecting the photosynthesis apparatus, antioxidants scavenging reactive oxygen species, providing camouflage, and attraction of pollinators and seed dispersers. Anthocyanins clearly fulfill different functions in different plant organs. It is currently believed that protective functions in leaves gave rise to the biosynthesis network and that flower and fruit coloration evolved later. Despite decades of research on the anthocyanin biosynthesis, there is still substantial potential for fundamental discoveries.

Digitalis purpurea (foxglove) is a widely distributed ornamental plant. Here, we present a long read sequencing-based genome sequence of a magenta 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 magenta 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. Furthermore, we found a large insertion in the DpTFL1/CEN gene to be likely responsible for the development of large terminal flowers.