COLLABORATIVE RESEARCH: Metabolomic Characterization of Red Light and CO2 Signaling in Guard Cells and Mesophyll Cells

Intellectual Merit. The research team plans to use modern biological tools to investigate the functions of metabolites in the processes of red light and carbon dioxide (CO2) regulated stomatal movement at the plant leaf surface. Stomata are microscopic pores enclosed by pairs of highly specialized epidermal cells called guard cells. Stomatal movements (enabled by volume changes in guard cells) control both CO2 uptake for photosynthesis and water loss from the plant to the atmosphere, and thus are closely related to plant growth, acclimation to environmental stresses such as drought, agricultural yield, bioenergy and human life. Red light and CO2 provide energy and the substrate for photosynthesis and biomass production. Red light and CO2 also regulate stomatal movement via intricate intracellular and extracellular signaling and metabolic networks. This research will elucidate and analyze these networks by studying the roles of metabolites synthesized by the guard cells or secreted by the major photosynthetic cells of the leaf in response to these signals. Dynamic changes of intracellular and extracellular metabolites upon red light and CO2 treatment will be characterized and correlated with the physiological output of stomatal movement. The project is expected to identify novel metabolites, place them in a functional context, and construct predictive molecular models of red light and CO2 signal transduction. The resources from this project will be distributed via a publicly accessible web interface for maximum scientific impact. The project is expected to contribute positively toward future biotechnology of enhanced plant yield and bioenergy.

Broader Impacts. This project is expected to generate results with broad societal impact, e.g., leading to rational plant metabolic engineering for enhanced stress tolerance, more food and bioenergy. The results will improve understanding of plant metabolism and signaling in guard cells and photosynthetic mesophyll cells, unravel the metabolic networks regulating stomatal function, and advance basic biological science. The techniques, data and resources developed during the project will be of immediate value to studies of other plant cells, pathways and species and will be disseminated via a web interface as well as in publications and at scientific conferences. The project will provide cross-disciplinary training of personnel, including high school students, undergraduate students, graduate students, and postdoctoral scientists, in the frontiers of modern biological sciences. Because large-scale and high-throughput metabolite analysis (metabolomics) is still in its infancy, a hands-on plant metabolomics workshop/symposium will be offered to graduate students and postdoctorates nationwide. Graduate students and postdoctoral scientists from the Chen and Assmann laboratories will be involved in developing and running the workshop, thus gaining valuable experience in teaching outside the standard classroom setting. Women and under-represented students will be recruited for the training opportunities. Overall, the training and outreach program is designed to integrate research and education to help prepare the next generation of plant scientists in the frontier areas of metabolomics, computational biology and the emerging disciplines of systems biology.