dr. L (Lotte) Caarls

I am a plant scientist interested in how molecular signaling processes in the plant immune system work, and how they govern plant interactions with pathogens and pests. At the Insect resistance group at Plant Breeding, I contribute to the development of plants with natural resistance to insect pests. We use state of the art tools to identify insect resistance traits in crop plants and their wild relatives and then genetically characterize the resistance and elucidate the mechanism on a molecular level.

Previously, I performed my PhD in the Plant-Microbe Interactions group in Utrecht, studying the phytohormones jasmonic acid, ethylene and salicylic acid, that are involved in plant defense. I investigated genes involved in the interaction between the three hormonal pathways. As the different hormones are involved in defense against different (types of) pathogens or insects, their interaction affects the outcome of defense. I also discovered novel enzymes in jasmonic acid metabolism, that turned out to inactivate jasmonic acid. Interruption of this inactivation resulted in very resistant plants, that were retarded in their growth, as hyperactivation of defense is often known to lead to reduction of growth.

I then moved to Wageningen UR, where I studied how plants can detect and defend to butterfly eggs. Butterfly eggs form a first warning to plants that attack by hungry caterpillars will follow. By killing or removing the eggs, the danger can be averted before damage is done. In my research, I aimed to find out how plants recognize attack by eggs, and how plants distinguish between different eggs to tailor their defense. To understand plant defense to eggs, I worked with several Brassicaceous species and eggs of several butterflies and moths. A major aim in this project was to identify the molecule in Pieris eggs that is detected by Brassica nigra (black mustard), and the gene involved in its recognition. In this project, I used molecular techniques to study the response of plants, performed chemical analysis of plant and insect metabolites and screened population to map the response.