Understanding the Biochemical Continuity of the ER and Chloroplast

Michigan State University, East Lansing MI

Investigators

Abstract

Chloroplasts are green organelles of plant cells and are the metabolic factories of the cell. Chloroplasts convert light into chemical energy, which is then used by the cell to synthesize hundreds of thousands of compounds upon which life on the planet depends. Like any factory, chloroplasts do not operate in isolation but rather collaborate with other organelles to synthesize most plant compounds. Collaborative synthesis is most common for non-polar (fat-soluble) compounds such as plant oils, pigments and volatile flavor compounds, but how non-polar biosynthetic intermediates move between plant organelles has remained unknown. The project builds on the discovery of a novel mechanism for this movement of compounds between organelles; to extend the factory analogy, we have found that rather than using carts to transport intermediates between organelles, as has long been assumed, the chloroplast and other organelles build a shared wall (membrane) which creates a common pool of non-polar intermediates to be accessed by enzymes in either organelle. The investigators will take biochemical, genetic and molecular approaches to test the range of compounds accessible at this interface and define its limits and operating principles. The resulting data will have broad implications and impacts in the engineering of plant metabolism to produce non-polar metabolites for food, feed, fuel and industrial applications. Training of undergraduates, especially for student's who are the first to attend college in their family, will be an integral component of the research. Data from these studies will be distributed to the public through peer-reviewed manuscripts or through seminars or talks and poster presentations at meetings. Once published, all transgenic or mutant lines, constructs, and other molecular tools will be either donated to the Arabidopsis stock center or will be provided upon request to interested parties in keeping with standard research practices.