ERA-CAPS: Designing C4 breeding strategies using genetic enablers of C4 evolution

光合作用是所有植物利用阳光、二氧化碳和水合成食物的过程。虽然大多数植物使用C3光合作用机制，但地球上产量最高的植物使用C4机制（C3和C4分别指参与光合作用的三碳分子和四碳分子）。除了产量更高，C4植物生长更快，需要更少的水和肥料，这表明如果更多的作物使用C4机制将是有价值的。然而，由于对C4光合作用的分子机制知之甚少，将C3植物转化为C4光合作用一直受到挫折。在陆生植物中，C4光合作用独立出现60次以上，仅芥菜科就有C3植物、C4植物和C3-C4中间植物。C3物种将与C3-C4中间体杂交，遗传学方法将用于帮助理解C4性状的关键基因和分子机制。收集到的知识将用于在C3植物中设计C4性状。这种转化无疑将提高作物产量，减少对水和肥料等投入物的需求，对社会和农业产生广泛影响。C4光合作用被地球上最高产的作物和原生植被所利用。然而，这一复杂性状的分子机制和遗传结构尚不清楚，这阻碍了将这一理想性状引入C3作物的努力。最近，在了解主要物种进化C4光合作用的机制以及导致完整C4性状的进化轨迹方面取得了重大进展。合成进化和基因编辑将被用于实验重现建立C4性状的最初步骤。初步光呼吸碳泵的建立降低了二氧化碳补偿点，诱导了原始的c4样碳循环，这一假设将得到验证。通过C3与C3-C4的种间杂交，通过数量遗传学鉴定C4进化的关键解剖生化因子。最后，基因组编辑和广泛的种内杂交将用于将C4使能剂引入C3芸苔科植物模型和油菜等作物。本项目将培养一名博士后，应用最新的基因编辑和合成生物学方法，鉴定C4中间体和光合作用的未知成分。此外，所获得的知识将用于测试C4中间体和光合作用的成分是否可以引入C3植物，最终目标是提高作物产量。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Photosynthesis is the process used by all plants to synthesize food from sunlight, carbon dioxide and water. Whereas most plants use a mechanism of photosynthesis called C3, the most productive plants on the planet use a C4 mechanism (C3 and C4 respectively refer to three-and four-carbon molecules involved in photosynthesis). In addition to being more productive, C4 plants grow faster and require less water and fertilizer, suggesting it would be of value if more crop plants used the C4 mechanism. Converting C3 plants to C4 photosynthesis, however, has been frustrated by the fact that molecular mechanisms enabling C4 photosynthesis are poorly understood. In the land plants, C4 photosynthesis arose independently more than 60 times, and in the mustard family alone there are C3 plants, C4 plants and C3-C4 intermediaries. C3 species will be crossed with C3-C4 intermediaries, and genetic approaches will be used to help understand key genes and molecular mechanisms enabling the C4 trait. Knowledge gleaned will be used to engineer the C4 trait in C3 plants. Such a conversion will undoubtedly increase crop yields and reduce the need for inputs such as water and fertilizer with broad impact for society and agriculture. C4 photosynthesis is used by the most productive crops and native vegetation on the planet. However, the molecular mechanisms and the genetic architecture underlying this complex trait are poorly understood, impeding efforts to introduce this desirable trait into C3 crops. Recently, significant progress has been made both in understanding the mechanisms that prime species to evolve C4 photosynthesis as well as the evolutionary trajectories that then lead to the full C4 trait. Synthetic evolution and gene editing will be used to experimentally recapitulate the initial steps that establish the C4 trait. The hypothesis will be tested that establishment of a rudimentary photorespiratory carbon pump reduces the carbon dioxide compensation point and induces a primordial C4-like carbon cycle. Inter-species crosses will be conducted between C3 and C3-C4 intermediate Brassicaceae species to identify key anatomical and biochemical enablers of C4 evolution by quantitative genetics. Lastly, genome editing and wide intra-species crosses will be used to introduce C4 enablers into C3 Brassicaceaen models and crops such as oilseed rape. This project will train a postdoctoral fellow on the application of the latest gene editing and synthetic biological approaches to identify unknown components of C4 intermediacy and photosynthesis. Further, knowledge gained will be used to test whether components of C4 intermediacy and photosynthesis can be introduced into C3 plants, with the ultimate goal of increasing crop yields.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.