"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Crassulacean acid metabolism (CAM), a photosynthetic pathway found in approximately 7% of all vascular plant species that improves water use efficiency up to 10-fold relative to C3 species, provides an exquisite example of circadian and environmentally regulated photosynthetic adaptation. CAM plants display distinctive circadian clock outputs and inverse stomatal rhythms, which are not found in C3 or C4 plants. The long-term goals of the proposed research are to identify the regulatory and signaling pathways essential for the circadian control of CAM and inverse stomatal behavior, respectively. The common or crystalline ice plant will be used as a model to determine the environmentally induced, circadian controlled changes in mRNA and protein abundance, and reversible protein phosphorylation events during the transition from C3 photosynthesis to CAM by conducting mRNA expression profiling. Metabolite changes will also be monitored to determine if they participate in possible feedback control circuits of upstream circadian clock gene expression outputs. Key regulatory and signaling factors that function in the CAM circadian clock will also be analyzed. Increased understanding of the molecular mechanisms responsible for controlling the expression and regulation of CAM will provide new knowledge about the molecular basis of this important water-saving photosynthetic adaptation that will provide novel strategies for improving crop productivity in the context of global climate change. This project will provide unique 'hands-on' training opportunities in plant research for undergraduate, graduate and post-doctoral students. Undergraduate students will be selected from established outreach programs at the University of Nevada (UNR) that target students from disadvantaged backgrounds to participate in developing a "Plants Have Rhythm" educational display and K-12 teaching module to inform and excite high school, college students, and the general public about CAM and the existence of circadian rhythms in plants and their adaptive significance.
