Single cell C4 Photosynthesis: Development and Function in Terrestrial Plants

植物的生长依赖于光合作用吸收大气中的二氧化碳。在干旱、盐碱地和高温等环境压力下，可用于光合作用的二氧化碳可能是一个限制因素，预计在全球变暖的情况下，这些条件会加剧。某些植物，包括许多杂草和少数粮食作物，使用一种被称为C4的光合作用机制，这种机制积极地积累大气中的二氧化碳。这提供了一种优势，特别是在那些极端的环境下。该项目的重点是C4陆地植物的物种，它们具有独特的碳获取形式，以及它在光合作用中的用途。在最近发现这种被称为单细胞C4的光合作用机制之前，C4植物的范例是两种细胞类型合作功能的要求(所谓的Kranz解剖学)。在单细胞C4物种中，存在着前所未有的光合作用细胞，其中包含两种类型的叶绿体，它们分别存在于不同的空间，一种专门支持主动捕获大气中的二氧化碳，另一种专门用于将其同化为有机物。需要研究的中心问题是叶绿体分化的控制机制(S)、空间区划的发展以及这些区划在光合作用中的作用。一般方法将包括使用显微镜、分子生物学、蛋白质鉴定和生理学。我们期待着深入了解光合作用的特殊机制，并为植物细胞组织、结构和生化分化提供新的模型。由于与Kranz解剖学相比，单细胞机制在物理上相对简单，因此单细胞机制可能有助于对水稻等作物进行工程改造，以获得更高的产量，特别是在全球变暖导致的气候变化下。通过教授和教科书中关于光合作用机制的信息，通过培训本科生和研究生以及接待来访的科学家，预计将在教育中产生更广泛的影响。

Plant growth depends on assimilation of atmospheric carbon dioxide (CO2) by photosynthesis. The availability of CO2 for photosynthesis can be a limiting factor under environmental stress, including drought, saline soils and high temperatures, conditions expected to exacerbate under global warming. Certain plants, including many weeds and only a few food crops, use a type of photosynthetic mechanism called C4 which actively accumulates CO2 from the atmosphere. This confers an advantage especially under those extreme environments. The project is focused on species of C4 land plants which have a unique form of carbon acquisition, and its usage in photosynthesis. Prior to the recent discovery of this type of photosynthetic mechanism, called single-cell C4, the paradigm for C4 plants was the requirement for cooperative function of two cell types (so-called Kranz anatomy). In the single-cell C4 species, there is the unprecedented development of photosynthetic cells containing two types of chloroplasts which exist in separate compartments, one specializing in supporting active capture of atmospheric CO2 and the other in its assimilation into organic matter. Central problems to be investigated are the mechanism(s) controlling chloroplast differentiation, the development of the spatial compartmentation and the role of these compartments in photosynthesis. The general approach will include use of microscopy, molecular biology, protein identification and physiology. We expect to gain insights into an exceptional mechanism of photosynthesis, and provide new models for plant cell organization, and structural and biochemical differentiation. Due to its relative physical simplicity compared to Kranz anatomy, the single-cell mechanism could be instrumental in engineering crops, such as rice, to produce greater yields, especially under climate changes occurring with global warming. Broader impacts are expected in education through teaching and textbook information on the mechanisms of photosynthesis, through training of undergraduate and graduate students and hosting of visiting scientists.