ConvergentDODA · Resolving the molecular basis underlying convergent evolution of DODA enzymes in the betalain synthesis pathway

Resolving the molecular basis underlying convergent evolution of DODA enzymes in the betalain synthesis pathway

Betalains are pigments found in plants belonging to the order Caryophyllales where they replace anthocyanins in most families, except for 6 families that produce anthocyanins. Betalains and anthocyanins are mutually exclusive as plants are able to produce betalains or anthocyanins but any plant producing both types of pigments has been described. The phylogenetic distribution of betalains and anthocyanin within Caryophyllales indicates multiple origins of betalains within Caryophyllales, from anthocyanic ancestors. The betalain biosynthesis pathway is led by 4,5-L-DOPA dioxygenase (DODA), the enzyme that catalyzes the ring cleavage of L-DOPA to yield betalamic acid, the chromophoric and structural unit of betalains. The distribution of betalain-producing families across Caryophyllales has been linked to the convergent evolution of DODA. Thus, there is evidence that betalain-producing plants do not share a common ancestor able to produce betalains but they have evolved independently 3-4 times. This project aims to understand the molecular modifications that DODA enzymes have experienced through their evolution and how they are related to the betalain-producing capacity detected in Caryophyllales plants. Studying DODA as a symbol of convergent evolution allows us to understand the molecular bases underlying the different approaches that organisms pursue to address similar evolutionary problems. The overall objectives are: - Biochemical characterisation of high-activity DODA enzymes - Characterisation of the ancestral biochemical function of the DODA enzymes - Identification of candidate residues for high DODA activity using ancestral sequence reconstruction - Validation of candidate residues using a high-throughput yeast heterologous expression system - Reconstruction of the evolutionary history of essential residues to understand evolutionary mechanisms for each origin of DODA

Data: CORDIS, © European Union