Tailoring of plant secondary metabolism in horticultural plant residuals by targeted stress application

Session 9. Valorization of bio-based industrial side streamsThe production of vegetables and fruits in greenhouses leaves large amounts of residual plant biomass behind, which represents a potential resource for the extraction of valuable secondary metabolites such as flavonoids. Various abiotic stresses induce selectively the biosynthesis of different secondary metabolites in plants. An application of targeted stress treatments in production greenhouses after the last fruit harvest could therefore increase the concentration of specific secondary metabolites in residual plants. Thereby, residual horticultural plant biomass is valorized, as it could be used for the extraction of valuable metabolites. In order to identify stress conditions that induce the accumulation of different valuable secondary metabolites, we measured the content of secondary metabolites of young tomato and bell pepper plants subjected to various abiotic stress treatments. In the projects InducTomE and TaReCa, we investigated the inducibility of selected flavonoids which are of interest due to their antioxidant potential and their bioactive properties, and of the polyisoprenoid solanesol. Additionally, metabolite screenings will be performed to discover further target metabolites of high value and industrial relevance. Thereby, we unfold the full potential of the plant residuals as source of secondary metabolites. To facilitate the implementation of stress treatment protocols in greenhouses and to allow a quality control of the valorized plant biomass, easy-to-use plant phenotyping technologies for the quantification of plant stress responses will be developed. In collaboration with project partners working on gene expression and metabolite analyses, transfer of induction protocols to commercial-like greenhouses, efficient extraction technologies, and an economic evaluation of the secondary metabolites extracted from residual plant biomass, we will demonstrate a proof-of-concept for the proposed valorization process. The proposed valorization and utilization of plant residuals for the extraction of valuable secondary metabolites will contribute to an increased sustainability in horticultural food production