16-ERACAPS. Designing C4 breeding strategies using genetic enablers of C4 evolution

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，这种复杂性状的分子机制和遗传结构知之甚少，这阻碍了将这种理想性状引入C3作物的努力。最近，我们和其他人在理解主要物种进化C4光合作用的机制以及随后导致完整C4性状的进化轨迹方面都取得了重大进展。这项建议建立在这些最近的发现，但结合了我们在C4光合作用的专业知识与合成实验进化的方法，旨在实验概括C4进化的最初步骤。使用这种方法，我们将把对复杂性状分子进化的机械理解转化为创新的育种方法，该方法由进化生物学提供信息，并由合成生物学和基因组编辑实现。为了实现这一目标，我们组建了一个由国际权威人士组成的新团队：广泛杂交以培育复杂性状（斯蒂奇），DNA编辑技术和合成生物学（Voytas），并将其与C4光合作用的专业知识相结合（Hibeland和Weber）。我们的具体目标是检验假设，即建立一个基本的光呼吸碳泵降低二氧化碳补偿点，并诱导一个原始的C4样碳循环;利用C3和C3-C4中间型菊科物种之间的种间杂交的力量，通过数量遗传学来确定C4进化的关键解剖和生化使能因子;最后，利用基因组编辑和广泛的物种内杂交，将C4使能因子引入C3拟南芥模型和作物，如油菜。

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 and this impedes efforts to introduce this desirable trait into C3 crops. Recently, we and others have made significant progress both in understanding the mechanisms that prime species to evolve C4 photosynthesis, and also the evolutionary trajectories that then lead to the full C4 trait. This proposal builds on these recent findings, but combines our expertise in C4 photosynthesis with a synthetic experimental evolution approach that aims to experimentally recapitulate the initial steps towards C4 evolution. Using this approach, we will translate the mechanistic understanding of the molecular evolution of a complex trait into an innovative breeding approach that is informed by evolutionary biology and enabled by synthetic biology and genome editing. To achieve this, we have assembled a new team made up of international authorities on: wide-crossing to breed complex traits (Stich), DNA editing technologies and synthetic biology (Voytas), and combined this with the expertise on C4 photosynthesis (Hibberd and Weber). Our specific aims are to test the hypothesis that establishment of a rudimentary photorespiratory carbon pump reduces the carbon dioxide compensation point and induces a primordial C4-like carbon cycle; to leverage the power of inter-species crosses between C3 and C3-C4 intermediate Brassicaceae species to identify key anatomical and biochemical enablers of C4 evolution by quantitative genetics; and lastly, to employ genome editing and wide intra-species crosses to introduce C4 enablers into C3 Brassicaceaen models and crops, such as oilseed rape.