Application of Eco-metabolomics in Biological Science

Secondary metabolites provide a tremendous potential for natural crop protection. This is especially important due to the rapid spread of agricultural pests worldwide. At the same time international law regulations restrict the use of synthetic pesticides. Therefore, we developed the eco-metabolomic approach to identify candidate compounds related to host plant resistance using NMR (Nuclear Magnetic Resonance Spectroscopy). We classify resistant and susceptible plants using in-vivo bioassays. Subsequently, we compare their metabolomic profiles by multivariate statistics to identify metabolites involved in host plant resistance. The negative effect of the candidate compounds is validated with in-vitro bioassays. As a proof of principle we used western flower thrips (Frankliniella occidentalis) a key pest worldwide. We applied the approach in different host systems including Senecio as a wild plant, chrysanthemum as an ornamental and tomato and carrot as vegetables. In all systems the metabolomic profiles of resistant and susceptible plants were significantly different leading to a range of different metabolites involved in thrips resistance. The majority of these compounds were phenylpropanoids and flavanoids. Interestingly, these did not only show a negative effect on thrips, but as anti-oxidants, were also linked to positive human health effects such as prevention of cancer and cardio-vascular diseases. As such these compounds do not only contribute to pest control but also to human health improvement. Therefore, our approach is of great relevance for application and implementation in sustainable crop protection programmes. Currently we are busy developing genetic and chemical markers of secondary metabolites to be incorporated in host plant resistance breeding. Besides we investigate the incorporation of secondary plant metabolites into seed treatments and the enhancement of plant secondary metabolite concentrations through the use of elicitors such a phytohormones, UV-light and bacteria.