Grant: Discovery Grants Program - Individual

Plant growth, development, and performance are defined by the shape of their roots, stems, leaves and floral organs, which is controlled by the dynamic polymer network known as the microtubule cytoskeleton that coordinates cell division as well as directional cell expansion. The proposed research program capitalizes on recent discoveries by the Wasteneys lab to understand the mechanisms that control the shape of plants. Microtubules are rod-like dynamic cytoskeletal polymers that interact with one another to self-organize into the cellular machinery that carries out work in eukaryotic cells. The first objective of this research program is to understand how microtubule self-organization works in plant cells. We intend to define how the proteins that associate with microtubules modify microtubule assembly activity and regulate encounters with other microtubules. Translating our live cell imaging data into computer simulations will allow us to develop a virtual model of this self-organization process. Our second objective will be to relate the organization of microtubule arrays to the mechanical properties of cell walls, which, in turn, control cell shape. Microtubules situated near the cell periphery interact with large enzyme complexes in the plasma membrane that synthesize and secrete the most abundant biopolymer on planet Earth, cellulose. Cellulose forms highly crystalline structures known as microfibrils, which are the major load bearing structures in plant cell walls. We have now developed methods for measuring the mechanical properties of cellulose microfibrils in expanding plant cells and will define these properties in relation to the organization of microtubule arrays. Understanding these mechanisms is thus a critical goal to understanding how the shape of plant cells is determined. But, with cellulose increasingly seen as an important renewable resource for and emerging biofuels industry, our discoveries are also a biotechnological opportunity.