I am interested in the interface between applied plant breeding and plant metabolism. In my master’s thesis we used classical breeding of passionfruit with the goal of releasing new varieties, now used by farmers. In my PhD thesis we studied carotenoid metabolism in melons and established a molecular marker now used routinely by melon breeders. More importantly, we suggested a novel non-transgenic path toward pro-vitamin A carotenoid biofortification of food crops. The objective the current OpenPlant project is to develop pre-breeding lines of beetroot for the production of L-DOPA.
L-DOPA is used to treat Parkinson’s symptoms; however, the current costs of chemical synthesis make it unavailable for deprived populations worldwide. In addition, there is a growing demand for ‘natural’ or plant sourced pharmaceutical substances in the first world. L- DOPA, a product of tyrosine hydroxylation, is an intermediate metabolite in biosynthesis of violet and yellow betalain pigments, in Beta vulgaris (table beet). L-DOPA natural steady state levels are very low, usually undetectable. We intend to block the turnover of L-Dopa in beetroot to allow its accumulation to levels that could enable low-tech accessible production in a plant system.
Current data indicate two betalain metabolic genes that, if repressed, may boost L-Dopa accumulation. Therefore, we aim to inhibit the activity of L-DOPA-dioxygenase, and L-DOPA-cyclase in beetroot. Currently, as proof of concept, we silence both genes in hairy roots system. We adopted three complementary strategies to meet the overarching objective of L-DOPA production in beet: a) Classical genetics; b) targeted genetic mutagenesis; and c) random mutagenesis. Yellow beet, mutated in L-DOPA-cyclase exists and can be crossed with “blotchy” red beet, which probably has lower L-DOPA-dioxygenase activity. Impairing L-DOPA-dioxygenase activity in yellow beet is carried out by both the targeted mutagenesis technology CRISPR/Cas9 and the random, yet more assured, EMS mutagenesis approach.