Molecular Mechanisms of CO2 Signal Transduction in Plants

植物叶片表面有成千上万个微小的可调节的气孔，称为气孔。这些气孔在叶子表面的打开和关闭，以调节植物从空气中吸收二氧化碳的必要性。然而，这些气孔也是植物通过蒸发失去水分的主要途径。一个典型的植物通过这些气孔损失200至500个水分子，每一个碳原子被植物吸收（同化）生长。气孔的打开和关闭由包括空气中二氧化碳（CO2）浓度的信号调节。与150年前相比，现在空气中的二氧化碳浓度高出50%，这意味着植物理论上可以更有效地从空气中吸收二氧化碳，同时损失更少的水。然而，重要的机制和基因，介导这农艺相关的CO2响应气孔孔径调节仍然未知。该项目将表征新发现的关键基因和蛋白质，并定义细胞网络，通过该网络，二氧化碳浓度升高控制气孔的关闭，以及二氧化碳浓度降低如何控制气孔的打开。这项研究可以发展必要的知识，以改善植物的生长特性和提高水分利用效率的育种。操纵气孔对二氧化碳的反应的能力对于不利的天气条件、农业地下水枯竭和干旱是重要的，这些在美国和全球的几个主要农业地区变得越来越频繁。科学家们将继续与研究实习，专业准备和辅导与公共普鲁斯学校在圣地亚哥县的弱势高中学生，以及培训和专业准备访问代表性不足的夏季研究实习生与加州大学圣地亚哥分校的ENLACE计划和霍华德大学的推广计划。项目人员将积极参与社区外展工作，使科学和创新接近公众，研究人员将通过与圣地亚哥市中心高中代表性不足的学生进行演讲和讨论，参与最近启动的外展计划。该项目将使用细胞生物学，生物化学，分子遗传学，数学建模，基因组和系统生物学方法，以确定新的关键分子组成的CO2信号网络，并表征该网络如何运作，以调节气孔孔径。本研究的主要目的是确定CO2刺激是如何进入气孔运动网络的，其目标是：（1）确定新发现的基因和编码蛋白介导早期CO2感受和信号转导的生化机制和网络原理。(2)新的假设将研究如何在叶片中的细胞对细胞的信号传导影响CO2控制气孔运动相结合的计算建模，遗传学，代谢组学和分子细胞生物学。(3)新分离的“寒冷”突变体，具有较冷的叶温度，并在草气孔的动态CO2响应中有缺陷，将被定位，至少一个限速基因的基础基因和蛋白质将被分离，其在特化哑铃形气孔运动中的功能-该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。

Plant leaves have thousands of microscopic adjustable pores in their leaf surface, called stomata. These stomatal pores in the surface of leaves open and close to regulate the necessary uptake of carbon dioxide into plants from the air. However, these stomatal pores also are the main pathway by which plants lose water, by evaporation. A typical plant loses 200 to 500 water molecules through these stomatal pores for every carbon atom that is absorbed (assimilated) by the plant for growth. The opening and closing of stomata is regulated by signals that include the concentration of carbon dioxide (CO2) in the air. The concentration of CO2 in the air is now 50% higher and rising, compared to only 150 years ago, meaning that plants could theoretically more efficiently take up CO2 from the air, while losing less water. However, important mechanisms and genes that mediate this agronomically relevant CO2 response of stomatal pore aperture regulation remain unknown. This project will characterize newly found key genes and proteins and define cellular networks through which elevated carbon dioxide controls the closing of stomatal pores and how low CO2 controls the opening of stomatal pores. This research can develop the knowledge necessary for the breeding of plants with improved growth properties and enhanced water use efficiency. The ability to manipulate the response of stomatal pores to carbon dioxide is important for unfavorable weather conditions, agricultural ground water depletion and droughts that are becoming more frequent in several of the major agricultural regions in the US as well as globally. The scientists will pursue an outreach program with research internships, professional preparation and mentoring with the public Preuss School for disadvantaged high school students in San Diego County, as well as training and professional preparation of visiting underrepresented summer research interns with UC San Diego's ENLACE program and with Howard University. Project personnel will be active within community outreach work that brings science and innovation close to the public and the investigators will participate in a recently launched outreach program through presentations and discussions with underrepresented students at inner city high schools in San Diego.This project will use a combination of cell biological, biochemical, molecular genetic, mathematical modeling, genomic and systems biological approaches to identify new critical molecular components of the CO2 signaling network and characterize how this network operates to regulate stomatal pore apertures. The focus of this project is to identify how the CO2 stimulus is transmitted into the stomatal movement network, with these goals: (1) Biochemical mechanisms and network principles will be determined by which newly identified genes and the encoded proteins mediate early CO2 sensing and signal transduction. (2) New hypotheses will be investigated on how cell-to-cell signaling in leaves affects CO2 control of stomatal movements by combined computational modeling, genetics, metabolomics and molecular cell biology. (3) Newly isolated "chill" mutants that have cooler leaf temperatures and are defective in the dynamic CO2 response of grass stomata will be mapped and the underlying gene and protein of at least one rate-limiting gene will be isolated and its functions in stomatal movements of the specialized dumbbell-shaped guard cells of grasses will be determined.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.