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

知识价值。研究小组计划利用现代生物学工具来研究代谢产物在红光和二氧化碳（CO2）调节植物叶片表面气孔运动过程中的功能。气孔是由一对高度特化的表皮细胞（称为保护细胞）所包围的微小气孔。气孔运动（由保护细胞的体积变化引起）既控制光合作用的二氧化碳吸收，又控制植物向大气的水分损失，因此与植物生长、对干旱、农业产量、生物能源和人类生活等环境胁迫的适应密切相关。红光和二氧化碳为光合作用和生物质生产提供能量和基质。红光和二氧化碳也通过复杂的细胞内和细胞外信号和代谢网络调节气孔运动。本研究将通过研究叶片保护细胞合成的代谢物或主要光合细胞分泌的代谢物对这些信号的响应作用来阐明和分析这些网络。细胞内和细胞外代谢物在红光和CO2处理下的动态变化将被表征，并与气孔运动的生理输出相关。该项目预计将识别新的代谢物，将它们置于功能环境中，并构建红光和CO2信号转导的预测分子模型。该项目的资源将通过一个可公开访问的网络界面进行分发，以实现最大的科学影响。预计该项目将对提高植物产量和生物能源的未来生物技术作出积极贡献。更广泛的影响。该项目预计将产生具有广泛社会影响的结果，例如，导致合理的植物代谢工程，以增强抗逆性，更多的食物和生物能源。研究结果将有助于进一步了解植物保护细胞和光合叶肉细胞的代谢和信号转导机制，揭示调节气孔功能的代谢网络，推动基础生物科学的发展。项目期间开发的技术、数据和资源将对其他植物细胞、途径和物种的研究具有直接价值，并将通过网络界面以及出版物和科学会议进行传播。该项目将为现代生物科学前沿的高中生、本科生、研究生和博士后提供跨学科的人才培养。由于大规模和高通量代谢物分析（代谢组学）仍处于起步阶段，因此将在全国范围内为研究生和博士后提供实践植物代谢组学研讨会。Chen和Assmann实验室的研究生和博士后科学家将参与开发和运行该研讨会，从而获得在标准课堂环境之外的教学的宝贵经验。将征聘妇女和人数不足的学生提供培训机会。总的来说，培训和推广计划旨在整合研究和教育，以帮助在代谢组学，计算生物学和系统生物学新兴学科的前沿领域培养下一代植物科学家。

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.