STTR Phase I: Metabolic engineering of photosynthesis for improved biomass accumulation

这个小企业技术转让（STTR）第一阶段项目提出通过光合途径的代谢工程来提高作物的内在产量。 编码用于光合作用和淀粉合成的五种限速酶的基因将在模式C4植物物种中组成型地或以细胞特异性方式共表达。 多种代谢途径将被改变，以同时减轻碳同化的多个限速步骤。 将测定酶积累对光合性能、植物生长和生物量积累的影响，并确定酶的最佳组合和相对酶水平。 将组成型酶积累的影响与细胞特异性酶积累进行比较，以确定靶向表达谱是否可以比组成型酶积累在碳同化速率和植物生长方面提供更实质性的改善。 这项工作的结果将确定关键限速酶的光合机制，最佳酶的表达谱，最佳的酶浓度，以提高光合性能，碳同化，和yield.The更广泛的影响/商业潜力，这个项目，如果成功的话，将确定新的方法来提高作物产量在一系列的粮食和非粮食作物。 光合工程改善碳同化是一个有前途的，但未充分开发，提高作物产量的方法。 传统的植物生物技术方法试图保护产量，例如通过抗虫性和除草剂耐受性。 利用合成生物学设计初级代谢和增加作物内在产量将与现有的产量保护技术协同工作。 建模和初步的概念验证研究已经证实，光合作用途径可以被设计成更高的效率，从而提高产量。 这项工作的结果将大大提高我们对光合碳同化的限速步骤的理解，为这些工程方法提供最有前途的反应和代谢途径。 将第一阶段工作的成果转化为作物将在不扩大农业足迹的情况下提高作物收成，从而为农业、食品和能源部门带来巨大的商业利益。

This Small Business Technology Transfer (STTR) Phase I project proposes to improve intrinsic crop yield through metabolic engineering of photosynthetic pathways. Genes encoding five rate-limiting enzymes for photosynthesis and starch synthesis will be co-expressed constitutively or in a cell-specific manner in a model C4 plant species. Multiple metabolic pathways will be altered to simultaneously relieve multiple rate-limiting steps for carbon assimilation. The effects of enzyme accumulation on photosynthetic performance, plant growth, and biomass accumulation will be assayed, and optimal combinations of enzymes and relative enzyme levels will be determined. The effects of constitutive enzyme accumulation will be compared with cell-specific enzyme accumulation to determine whether a targeted expression profile can deliver a more substantial improvement in carbon assimilation rates and plant growth than constitutive enzyme accumulation. The results of this work will identify key rate-limiting enzymes in the photosynthetic machinery, optimal enzyme expression profiles, and optimal enzyme concentrations to improve photosynthetic performance, carbon assimilation, and yield.The broader impact/commercial potential of this project, if successful, will be to identify novel ways to improve crop yields in a range of both food and non-food crops. Photosynthetic engineering for improved carbon assimilation is a promising, but underexplored, method for improving intrinsic crop yield. Traditional plant biotechnology approaches have sought to protect yield, e.g. through insect resistance and herbicide tolerance. Utilizing synthetic biology to engineer primary metabolism and increase intrinsic crop yields will work in tandem with existing yield-protecting technologies. Modeling and initial proof-of-concept studies have confirmed that photosynthetic pathways can be engineered for greater efficiency, resulting in yield improvements. The results of this work will significantly enhance our understanding of the rate-limiting steps of photosynthetic carbon assimilation, providing insight into the most promising reactions and metabolic pathways for these engineering approaches. Translating the results of this Phase I work to crop plants will result in improved crop harvests without expanding the agricultural footprint, translating to enormous commercial benefits to the agricultural, food, and energy sectors.