All land plants are pigmented by flavonoids and their anthocyanin derivatives, with one exception. In the order Caryophyllales, which contains the colourful beetroot, anthocyanins have been replaced with a pigment type called Betalains.
Collaborative research between the Brockington Lab and colleagues at the University of Michigan, and Oberlin College, USA has revealed the genetic origins of the betalain pathway. The research demonstrates that lineage-specific radiations of cytochrome P450 and 4,5-dioxygenase genes within the Caryophyllales simultaneously gave rise to new enzymatic isoforms associated with betalain synthesis. The novel isoforms likely evolved new substrate specificities that allowed them to synthesise betalains from tyrosine precursors. These discoveries open a range of possibilities with respect to the genetic engineering of betalain pigmentation.
The work is published in two linked papers in Molecular Biology and Evolution and the New Phytologist, and was funded by NERC and the National Science Foundation. Julian Hibberd with Sarah Covshoff enabled this research through the generation of 1KP transcriptomes.
- Yang Y, Moore MJ, Brockington SF, Soltis DE, Wong GKS, Carpenter EJ, Zhang Y, Chen L, Yan Z, Xie Y, Sage RF, Covshoff S, Hibberd JM, Nelson MN, Smith SA (2015) Dissecting molecular evolution in the highly diverse plant clade Caryophyllales using transcriptome sequencing. Molecular Biology and Evolution doi:10.1093/molbev/msv081
- Brockington SF, Yang Y, Gandia-Herrero F, Covshoff S, Sage RF, Hibberd JM, Wong GKS, Moore MJ Smith SA (2015) Lineage-specific gene radiations underly the evolution of novel betalain pigmentation in Caryophyllales. New Phytologist [early view online]