The Chloroplast Copper Delivery System

养分的有效性可以限制植物的生长和生产力。植物需要微量元素铜来进行光合作用，在这个过程中，阳光被用来固定大气中的二氧化碳，这是地球上所有生物质形成的原因。然而，除了光合作用，其他过程也需要铜。因此，当土壤中这种元素的含量有限时，植物必须选择如何最好地利用这种宝贵的资源。研究发现，控制铜在植物叶片细胞内如何使用的运输系统受到可用铜量的调节。调控机制涉及光合亚细胞区室中铜转运体的铜控制选择性降解。这一发现表明，植物可以选择性地感知叶片中不同细胞区室中可用的铜的数量，而这一信息反过来又用于控制特定蛋白质的稳定性。这种机制以前在自然界中没有观察到，本研究旨在确定可以感知铜和控制转运蛋白周转的细胞机制。这一调控过程对光合生产力的影响将被测试。微量营养素的可用性如何影响光合作用机制的组装是细胞生物学中必须解决的一个基本问题。更广泛的影响光合作用是驱动地球上所有生命的过程。更好地了解光合作用机制是如何组装的，将使人们在使用肥料和铜基杀菌剂方面做出更好的决定，从而有利于环境，并有可能提高农业生产力，特别是在边缘土壤上。这项研究对生物燃料生产也有潜在的影响，因为生物燃料生产需要最佳的光合作用。该项目将培训一批年轻科学家，其中包括科罗拉多州立大学的本科生，并以植物生物学和光合作用模块的形式为当地小学提供拓展部分。

INTELLECTUAL MERITNutrient availability can limit plant growth and productivity. Plants need the micronutrient copper to perform photosynthesis, the process in which sunlight is used in order to fix carbon dioxide from the atmosphere and which is responsible for all biomass formation on the planet. However, copper is also required for other processes, next to photosynthesis. Therefore, when this element is available in limiting amounts in the soil, choices must be made by the plant about how to best use this precious resource. It was found that the transport systems that control how copper is used within the cells of a plant leaf are regulated by the amount of copper that is available. The mechanism of regulation involves a copper-controlled selective degradation of a copper transporter within the photosynthetic sub-cellular compartment. This finding implies that plants can selectively sense the amount of copper that is available in various cellular compartments within a leaf and that this information in turn is used to control specific protein stability. Such a mechanism had not been observed before in nature and this research is aimed at identifying the cellular machineries that can sense copper and that control transporter turnover. Implications of this regulatory process for photosynthetic productivity will be tested. How micronutrient availability affects the assembly of the photosynthetic machinery is a fundamental question in cell biology that has to be addressed. BROADER IMPACTSPhotosynthesis is the process which drives all of life on earth. A better understanding of how the photosynthetic machinery is assembled will allow people to make better decisions regarding the use of fertilizers and copper-based fungicides, thus benefitting the environment and potentially improving agricultural productivity, especially on soils that are marginal. The research also has potential impact for biofuel production in which optimal photosynthetic activity is required. The project will train a group of young scientists including undergraduate students at Colorado State University and includes an outreach component for local elementary schools in the form of modules about plant biology and photosynthesis.