EAGER: Lipids on the move

Michigan State University, East Lansing MI

Investigators

Abstract

Plants are essential for all life on earth: they provide the oxygen we breathe, medicines, raw materials for industry and construction, fuel, nutrition, and food. Globally, 62% of harvested crop is used for human food, 3% to produce seeds for replanting, bioenergy, and industrial products, and 35% for animal feed. The priority goals of the United Nations include "End hunger, achieve food security, improve nutrition, and promote sustainable agriculture". This is not a trivial goal as plants are quite literally "rooted to the spot" and cannot escape adverse conditions. It is essential to understand how plants sense environmental changes, signal these changes to other parts of the plant and adjust development accordingly. Lipids are oil and fat-soluble molecules that play an important role in plant and animal development and serve as signals for changing environmental conditions. As a result, understanding the function of plant lipids and the mechanism of their transport will serve not only the scientific understanding of plant developmental processes but will also translate into tangible improvements of food sustainability and quality: - Understanding how lipids affect plant growth and seed and fruit development will lead to higher yields and more food. - Understanding how lipids affect plant survival in changing environments (cold, freezing, drought, nutrient-deficient soil, insect feeding etc.) will reduce crop losses. Lipids are essential components of plants. They provide energy for metabolic processes, are membrane components, and serve as intracellular signals. Simple lipids such as oxylipins are long-distance signals of biotic stress suggesting other lipids function as systemic signals as well. Given the fundamental importance of mobile signals for the coordination of abiotic stress and development, and thus for plant survival and food security, it is imperative to unequivocally demonstrate the existence of long-distance phospholipid-signaling and its components. The PI's lab has identified the lipid phosphatidic acid (PA) and a PA-binding protein (PLAFP) in phloem exudates and proposed that phloem lipid-binding proteins, particularly PLAFP and PA act in development and in long-distance signaling in response to environmental stress. To test this hypothesis, the lab will - Investigate localization and movement of the protein PLAFP using a combination of transgenic approaches, grafting, western blot, confocal microscopy, immunogold labeling and NightOWL imaging. - Monitor lipid movement in wild type, PLAFP-overexpression and PLAFP knock-down plants. MS will confirm the identity of the radiolabeled mobile compound. - Determine binding mechanisms and specificity of the PLAFP-PA complex and its movement using a combination of a "Red-Light-ON" optogenetic switch with a novel FRET approach that visualizes protein-lipid interaction in vitro and in-planta. Once established this system will provide a tool to study protein-ligand interactions in any system. The work will be assisted by a postdoctoral researcher, a graduate student, and an undergraduate. They will be able to participate in an international collaboration/exchange with the Heinrich-Heine University Duesseldorf, Germany. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.