Steroidal glycoalkaloids (SGAs) are a class of antinutritional substances found in staple vegetable crops such as potato, eggplant, and tomato. As SGAs are not destroyed during the cooking process, they remain in our food chain and daily diet and cause gastrointestinal and neurological disorders. At high concentrations, they may be even lethal, and for this reason, strict guidelines have been implemented to limit SGAs content in potato tubers. A limit is suggested for eggplants, but no guideline has been established yet for this crop. Moreover, because light induces SGAs production in potato tubers, producers and resellers must take great care to store tubers in the dark until they reach the consumer. This precaution increases the cost of the potato to the consumer. Consequently, commercial potato cultivars have been bred to contain low SGA levels, but despite these efforts, between 13 and 27% of the potato crops are discarded worldwide because SGA levels exceed the maximum currently deemed to be safe. Therefore a strategy to prevent SGAs accumulation in such crops is particularly needed, and as a consequence potato breeding companies and growers are extremely interested in this quality trait.While major attention has been given to increase nutritional substances in food plants (e.g. vitamins), only limited efforts have been made for using biotechnological approaches to reduce the level of endogenous, anti-nutritional factors (e.g. toxic compounds) in existing crops. In this study, we intend to redesign the metabolic pathways of potato and eggplant crop plants in a precise manner, through targeted knockout of genes that reduce the poisonous value of the crop. Notably, this strategy does not leave foreign genes present in the final plant product, and as a result the plants coming from this research will be non-GMOs. Specifically, we will target a set of genes that were identified in the course of our ERC grant research, using state of the art technologies for gene knockout. These genes are involved in the production of the SGAs compounds discussed above, and the disruption of these genes will strongly reduce the content of these poisonous compounds in potato and eggplants. In the course of this project, we have developed an efficient gene knock-out system that allowed successful gene knock-out in plants, particularly tomato. This system is extensively described below as well as in a recent patent application. To date, we have managed to generate mutations in several genes of interest in tomato plants, and we are attempting to mutate additional genes in potato and eggplant. This demonstrates that the strategy suggested here is suitable to reduce potatoes and eggplants toxicity in a non-GMOs manner. We expect that in the near future, we will be able to generate the crops of interest and transfer them to seed companies for further breeding. This project also highlights the benefit of biotechnological approaches to improve agricultural traits and food quality.
