Soaps help plants: Exploiting plant defense compounds to improve disease resistance in chrysanthemum.

Saponins are bitter-tasting defence compounds with detergent ("soapy") properties. They are produced by many plant species and contribute to pest and disease resistance. However, the chemical structures and role of saponins in many plant species remain unknown, and they have not been exploited in commercial crop breeding for pest and disease resistance. In our previous study, we discovered the importance of a-tomatine, a saponin of tomato, and identified the tolerance mechanisms of the plant-pathogen Botrytis cinerea to a-tomatine. Based on those findings, the project aims to translate the knowledge emerging from Tomato-Botrytis interaction to the ornamental Chrysanthemum and investigate the potential of saponins in breeding for disease resistance. This study aims to identify saponin-rich cultivars and functionally evaluate them using cutting-edge sensor strains developed in my previous research. Elucidating the chemical structure of chrysanthemum saponins with high efficacy against pests and diseases opens perspectives for breeding chrysanthemum for resistance. Furthermore, the project aims to identify the mechanisms by which fungal pathogens of chrysanthemum (Botrytis and Fusarium) can become tolerant to saponins and identify the regulators involved in the response to membrane damage caused by saponins. Lastly, the project aims to design and evaluate chemical compounds that can inhibit some of the protective mechanisms in fungi against saponins, thereby acting as a "potentiator" of plant defense compounds. Such an inhibitor might have agrochemical applications, as it would reinforce the efficacy of the plant’s natural defences.