Dissecting the Molecular Mechanisms Underlying Intimate Relationship between Cellulose Microfibrils and Cortical Microtubules

Intellectual Merit. Cellulose, an organic compound found in all plants, is the most abundant biological material on earth. Cellulose constitutes the major raw material that is used to produce paperboard, paper, lumber, and textiles. It is also one of the main sources of biomass for the production of renewable biofuels in the near future. Despite overwhelming interest, little is known about how plant cells make cellulose. Cellulose is synthesized by cellulose synthase complexes. Cellulose synthase complexes had long been proposed to interact with cortical microtubules, fibrous structural components within cells, before recent live cell imaging showing that cellulose synthase complexes move on trajectories that parallel the underlying cortical microtubules. Yet a molecular link between microtubules and cellulose synthase complexes is missing. The principle investigator recently identified the first interacting protein of cellulose synthase complexes, named CSI1, which is an excellent candidate for the missing link. The project is aimed to characterize CSI1 with respect to its interactions with cellulose synthase complexes and microtubules. Researchers will use a battery of genetic and biochemical assays and also high-end microscopy to study the connection between cellulose synthase complexes and microtubules, and determine how these connections developed inside the plant cells.

Broader Impacts. The development. of alternatives to fossil fuels as an energy source is an urgent global priority. Lignocellulosic biomass in the form of plant materials (for example, grasses and woody species) offers the opportunity of a renewable, relatively greenhouse-gas-neutral source of sugars that can be converted to ethanol and other liquid fuels. Considering cellulosic biomass are expected to become one of the main sources of biomass for the production of renewable biofuels, understanding the mechanism by which plant cells make cellulose may be of great interest for energy producing agents. The basic knowledge gained from understanding how plants make cellulose will be applied to modify bioenergy crops with regard to traits related to the composition and overall content of biomass. The project will also offer great training opportunities to young scientists including undergraduate, graduate students, and postdocs. This project will allow principal investigator to participate in outreach programs offered by Eberly College of Science at Penn State University, the summer workshop for K-12 teachers and/or students, and High-School Science Project aimed to improve the scientific knowledge of the general group or a specific student group outside of a school setting.