Mechanisms of C4 Photosynthetic Evolution

C4光合作用通过抑制光呼吸的浪费过程，提高高等植物的生产力和资源利用效率。尽管有其优势，但很少有主要的粮食和纤维作物使用C4途径，而是依赖C3途径，而C3途径可能会受到高速率光呼吸的影响。为了满足日益增长的对食物、纤维和燃料的需求，人们对进一步开发C4光合作用非常感兴趣，无论是通过工程C4途径转化C3作物，改良现有的C4作物，还是驯化野生C4物种。多伦多大学的Sage实验室是C4植物生物学领域公认的领导者，在分子机制、基因组学、全植物生理学、光合作用进化、系统学和生态学/生物多样性之间拥有专业知识。通过我们的努力，我们已经证明了C4光合作用至少进化了65次，这表明它在自然界中进化相对容易，对人类来说，改造成我们的C3作物，如小麦和水稻。通过研究C4植物是如何进化的，我们应该能够学习如何将C4途径改造成C3植物，并改进现有的C4作物。在这项提案中，要求资金支持将阐明控制C4光合作用进化的生理、发育和分子机制的研究。为了支持这项工作，我们从34个独立的C4光合作用起源获得了世界上最大的相关C3、C4和C3-C4中间物种的集合，其中包括来自9个C4进化谱系的不同的C3-C4中间物种。这种多样性将使我们能够使用比较的方法来研究C4光合作用进化的生理、发育和分子机制。在比较研究中，我们将沿着进化梯度描述C4性状的获得，如

C4 photosynthesis enhances productivity and resource-use efficiency in higher plants by inhibiting the wasteful process of photorespiration. Despite its advantages, few major food and fiber crops use the C4 pathway, relying instead on the C3 pathway which can suffer from high rates of photorespiration. To meet growing demands for food, fiber and fuel, there is much interest in further exploiting C4 photosynthesis, either through the engineering of the C4 pathway into C3 crops, improving existing C4 crops, or domesticating wild C4 species. The Sage lab at the University of Toronto is a recognized leader in C4 plant biology, with expertise at the interfaces between molecular mechanisms, genomics, whole plant physiology, photosynthetic evolution, systematics, and ecology/biodiversity. Through our efforts, we have shown that C4 photosynthesis evolved at least 65 times, indicating it is relatively easy to evolve in nature and for humanity to engineer into our C3 crops, such as wheat and rice. By studying how C4 plants evolved, we should be able to learn how to engineer the C4 pathway into C3 plants, and to improve existing C4 crops. In this proposal, funds are requested to support research that will elucidate the physiological, developmental, and molecular mechanisms governing the evolution of C4 photosynthesis. To support this work, we have acquired the world's largest collection of related C3, C4 and C3-C4 intermediate species from 34 independent origins of C4 photosynthesis, including a diverse set of C3-C4 intermediate species from nine C4 evolutionary lineages. This diversity will enable us to use a comparative approach to examine the physiological, developmental and molecular mechanisms by which C4 photosynthesis evolved. In the comparative studies, we will characterize C4 trait acquisition along an evolutionary gradient in genera such as