PhD Defence Line Lykke Hansen
You are all invited for the PhD defence of Line Lykke Hansen
The title of her PhD thesis is: Using an untargeted transportomic approach for exploration of Arabidopsis thaliana ABCG transporters
Summary:
Transport proteins are essential for plant fitness and survival because they facilitate the distribution of metabolites important for growth, development, and defence. Within the plant, correct distribution of phytohormones ensures proper physiological responses, while the distribution of defence compounds such as glucosinolates is crucial for deterring herbivores and pathogens. In addition to the internal translocation of substrates, transport proteins are also essential for plants to interact with their immediate environment. Exported metabolites are involved in responses to biotic and abiotic stresses, as well as the recruitment of a beneficial microbiome to the plant surface both above and below ground. However, despite the critical functions of transport proteins, there is a significant gap in the identification and characterization of export proteins.
In this study, we developed an untargeted transportomic approach to screen for export activity of members of the ATP BINDING CASSETTE transporter subfamily G (ABCG) from Arabidopsis thaliana using Xenopus laevis oocytes. By optimizing metabolite extraction procedures, we prepared Arabidopsis leaf extracts compatible with injection-based export assays and used the extracts to screen for the export activity of half-size ABCG transporters. By coupling both targeted and untargeted metabolite profiling in data analysis, transport activities towards multiple metabolites can be simultaneously identified. The results include the identification of one ABCG protein as a novel glucosinolate and hormone transporter and we present the initial efforts to characterize its biochemical and physiological role in planta.
The study provides a method applicable to the analysis of export activity of theoretically any given transporter. Ultimately, assigning substrates to protein exporters will help to identify new targets for transport engineering that can be used to improve crops in sustainable agriculture.
Principal supervisors:
Professor Barbara Ann Halkier, Section for Molecular Plant Biology
Dr Deyang Xu, Section for Molecular Plant Biology
Assessment committee:
Associate professor Fernando Geu-Flores, Department of Plant and Environmental Sciences (Chair)
Associate professor Pilot Guillaume, Virginia Polytechnic Institute and State University, US (External member)
Senior lecturer Markus Geisler, University of Fribourg, Department of Biology (External member)