Plant growth and development are achieved by the combined effect of two fundamental cellular processes, cell division and cell growth. This project aims at understanding an extreme form of polarized cell growth called tip growth, which occurs in root hairs, pollen tubes, and the filamentous cells of ferns and mosses. It is well established that tip growth is dependent on the actin cytoskeleton. This cytoskeleton is a cellular structure composed of nanometer size fibers. In cells, molecular motors called myosins interact with these fibers for contraction and intracellular transport. Despite the long known role of the actin cytoskeleton in tip growth, it is not known how this cytoskeleton is linked to growth. This project aims to evaluate if a plant specific myosin (myosin XI) is the link between the actin cytoskeleton and tip growth. To help understand myosin XI function, the investigators will determine its location within the cell. In addition, by preventing myosin XI expression, they will determine if myosin XI regulates the actin cytoskeleton or intracellular transport. These studies are being carried out in the emerging plant model, the moss Physcomitrella patens. This organism was chosen because of its unique genetic properties and simple development. Furthermore, a recently completed genome sequence facilitates the generation of molecular tools. As the primary producers of food and biofuel, plants are an essential component for the establishment of a sustainable future. Hence, understanding plant growth is an important endeavor of basic science, potentially becoming the basis of vital new technologies. The investigators are committed to increasing the participation of underrepresented groups in the life sciences. Throughout this project, students and postdoctoral researchers who are members of these groups will be actively recruited, trained and mentored. By coordinating with other organizations, support will be provided for undergraduate students to complete summer projects and full year internships.
