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Feeding herbivores induce direct and indirect defence mechanisms in plants both of which involve chemical compounds. Direct defence might be an increased concentration of toxic alkaloids in nightshades, indirect defence might be the attraction of the herbivore natural enemies by emitting volatile organic compounds. Abiotic constraints can increase constitutive chemical defence in plants but there is a lack of information regarding induced defence. Nitrogen and water availability are crucial factors in crop production both in terms of yield and environmental compatibility. Excessive nitrogen input leads to eutrophication while, in a changing global climate, water is becoming even more precious in dry regions like the Mediterranean. Studies indicate that nitrogen and water limitation can impact the production and/or emission of herbivore-induced plant volatiles. Additionally, these factors can trigger bottom-up effects by altering plant nutritional value and toxicity which in turn affects herbivores and thereby their natural enemies. Predatory and parasitoid insects are used as biological control agents in crop production systems. This kind of integrated pest management could be improved by a better coordination of biotic and abiotic measures. My objective is to gather detailed information on the impact of nitrogen and water limitation on defence compounds of tomato plants. Furthermore, I want to optimize abiotic conditions to support the natural enemies efficiency while possibly reducing the use of water and nitrogen into for crop production. I use insect herbivores from different feeding guilds because the plant response to them can vary and lead to different changes in chemical composition and trophic cascades.
I studied biology at the University of Wurzburg, Germany, where I specialized in plant physiology, chemical ecology, and plant-insect interactions. For my PhD thesis at the Berlin Technical University and the Leibniz-Institute for Vegetable and Ornamental Crops, GroBbeeren, Germany, I investigated the impact of abiotic factors (light, temperature, CO2 and nutrient availability) on the concentration of flavonoids and phenolic acids in lettuce.
From 2015, in the frame of an AgreenSkills fellowship, I worked at ISA (Institute Sophia Biotech) at Nice Sophia Antipolis. I studied the effect of abiotic factors (water and nutrient availability) on plant-mediated multitrophic interactions in the tomato agro-ecosystem, including plant nutritional and defense quality, plant volatiles and insect performance.
In 2018, I started a position at Geisenheim University, Germany, department of Crop Protection. I continue to investigate the effect of abiotic factors (elevated atmospheric CO2-concentrations) on plant-herbivore interactions. Focussing on the herbivore, I study changes in its gene expression, development, and behaviour related to changes in plant quality.
Dannehl, D., Becker, C., Suhl, J., Josuttis, M., Schmidt, U., 2016. Reuse of organomineral substrate waste from hydroponic systems as fertilizer in openfield production increases yields, flavonoid glycosides, and caffeic acid derivatives of red oak leaf lettuce (Lactuca sativa L.) much more than synthetic fertilizer. J. Agri. Food Chem., 64 (38): 7068-7075.
Becker, C., Desneux, N., Monticelli, L., Fernandez, X., Michel, T., Lavoir, A.V., 2015. Effects of abiotic factors on HIPV-mediated interactions between plants and parasitoids. BioMedResearch 2015, Article ID 342982, 18 pages.
Becker, C., Urlic, B., Jukic Spika, M., Klaering, H.-P., Krumbein, A., Baldermann, S., Goreta Ban, S., Perica, S., Schwarz, D., 2015. Nitrogen limited red and green leaf lettuce accumulates flavonoid glycosides and caffeic acid derivatives while losing chlorophylls, B-carotene and xanthophylls. PLoS ONE 10: e0142867.
Becker, C., Klaering, H.-P., Schreiner, M., Kroh, L.W., Krumbein, A., 2014. Unlike Quercetin Glycosides, Cyanidin Glycoside in Red Leaf Lettuce Responds More Sensitively to Increasing Low Radiation Intensity before than after Head Formation Has Started. J. Agri. Food Chem., 62: 6911-6917.
2014 National German Sustainability Award for ZINEG project (context of PhD thesis);
2014 Poster Award, 49. Jahrestagung DGG & BHGL, March 3rd-5th,
2014, Dresden, Germany;
2013 PhD dissertation with distinction;
2012 Poster Award, 8th Plant Science Student Conference, June 4th-7th
2012, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany.