This project explores the function of a new class of plant proteins that are located at the periphery of the nucleus - the center of genetic information - in the plant cell. These enigmatic protein complexes connect the inside of the nucleus to the cytoplasm - the part of the cell that surrounds the nucleus - and are important for a number of plant functions. This project will explore two functions. First, their role in pollen tubes, which are essential for fertilization and seed production (grain yield) in flowering plants. And second, guard cells, the cells that control the opening and closing of apertures (stomata) in the leaf of the plant, which regulate the movement of carbon dioxide from the air into the plant, and the loss of water (as vapor) from plant leaves into the air. The uptake of carbon dioxide from the air and the loss of water from the plant are of added significance in the face of increasingly frequent climate events such as drought, temperature extremes and the rising levels of carbon dioxide in the earth's atmosphere. In addition to training postdoctoral scientists, and graduate and undergraduate students, in cell and molecular biology, the project will initiate and develop an outreach project involving art to visualize aspects of the research and present them to the broader public.
Plant-specific outer nuclear envelope proteins (KASH proteins) are the functional equivalent of animal KASH proteins of the linker of nucleoskeleton and cytoskeleton (LINC) complexes. This project will dissect how KASH proteins function in plant male fertility and guard cell aperture regulation. One plant specific LINC complex is required to move the vegetative nucleus through the pollen tube and its disruption affects pollen tube termination and male fertility. The connection of this newly discovered process to known signaling pathways of pollen tube function, including ROS and calcium signaling, will be determined; mathematical modeling will be applied to simulate the movement of the vegetative nucleus and the defects caused by the mutants; and motor proteins will be identified that interact with the LINC complex and are involved in the movement. A second plant-specific LINC complex is located at the nucleus of guard cells and its disruption changes guard cell abiotic stress response, and guard cell dynamics. The connection between this LINC complex, guard cell cortical actin patterns, nuclear calcium signaling, and vacuolar morphology will be dissected. In addition, candidate proteins for a plant lamina will be tested for interactions with the plant LINC complexes and for their involvement in the guard cell and pollen tube biology described above.
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.
