Subcellular Localization of Signal Molecules and Their Effect on Plants (Biological Sciences)

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This project will take a two-pronged approach to give greater insight into how signals are perceived and transduced into responses in plant cells. (1) Rhizobium bacteria induce the formation of nitrogen fixing nodules in plants and together they provide the major input of biologically fixed nitrogen in agriculture. Cellular and molecular biological methods will be brought to bear on the analysis of early events of nodulation (nod gene mechanisms) of root hairs in the Rhizobium meliloti-alfalfa system (with Sharon Long). A newly developed method will allow bacterial cells and purified "nod factors" to be applied to or injected into single root hair cells. Video- enhanced (including confocal laser scanning) light microscopic images will permit the in vivo observations of induced responses in nodulating root hair cells, and these images will be correlated with in vitro electron microscopic images. Transient and longer response changes in internal calcium ion levels, cytoskeletal elements, calmodulin and the endoplasmic reticulum will be examined. A clearer understanding of the cellular, genetic and molecular aspects of nodulation should result. (2) The photoreceptor phytochrome mediates a host of light-activated developmental processes in plants. Monoclonal and polyclonal antibodies against phytochrome will be used to detect and localize (video microscopically) the distribution of the membrane-associated fractions of phytochrome in pea stem vesicles, and if that is successful, in cells (with Winslow Briggs). Interactive activities will consist of a course entitled Gender and Science, taught to undergraduate and graduate students from different disciplines in the sciences and humanities; lectures in a "Microscopy for Biologists" course on video-enhanced, computer-based microscopic methods; several seminars; and organization of informal panel discussions on several topics pertinent to women (and men) in science. This project furthers VPW program objectives which are (1) to provide opportunities for women to advance their careers in engineering and in the disciplines of science supported by NSF and (2) to encourage women to pursue careers in science and engineering by providing greater visibility for women scientists and engineers employed in industry, government, and academic institutions. By encouraging the participation of women in science, it is a valuable investment in the Nation's future scientific vitality.