RoL: FELS: EAGER: Simple scaling rules that define how genome size constrains metabolism: a test among photosynthetic pathways

新陈代谢和细胞结构变化之间的协调，以及基因组大小和细胞大小之间的协调，在所有生命中都被广泛观察到。这些关系的性质及其对生物多样性产生的影响仍然不清楚。这个项目将通过研究维管植物的细胞解剖学和基因组大小如何随着时间的推移与光合作用新陈代谢的变化相关联，来解决我们对这一潜在的“生命规则”的理解上的差距。研究人员将结合来自维管植物生命树的比较解剖学、系统发育和基因组数据，阐明基因组基本结构的变化--它的大小--如何与细胞的大小相关，以及随后单个细胞和整个生物体如何处理能量。该项目将培训本科生，包括来自代表性不足群体的个人，并促进具有不同专业知识的项目团队成员之间的合作，这些成员大多是职业生涯早期的研究人员。这项研究的社会效益包括发现生物学中新的基本比例法则的可能性，以及开发更多高产农业作物的新途径。该项目将测试基因组大小、细胞大小和新陈代谢之间的协调是否代表了限制有机体表型多样性的基本生命规则。研究人员将使用维管植物作为模型系统，因为随着进化时间的推移，维管植物的谱系在C3、C4和CAM光合代谢之间反复变化，因此提供了对最重要的假设的多个独立测试。研究人员将在大约360种维管植物中确定不同光合代谢对基因组-细胞异速生长的依赖，这些维管植物包含光合作用途径之间的多个转变。样本将包括已知有许多C4和CAM转变的开花植物分支，包括草和菠萝科单子叶家族，以及含有仙人掌(石竹目)的优生目。所有物种的基因组大小和解剖特征(叶表皮、保卫细胞和脉的大小和密度)将被量化。对于物种的一个子集，将使用MicroCT成像来测量叶片细胞的三维结构和组织。然后，研究人员将通过分析288个完整的植物基因组来表征维管植物基因组在大小和组成方面的变化。比较分析将揭示与光合代谢变化相关的基因组结构，并将揭示与裸子植物近亲相比，早期分叉的开花植物是如何缩小其基因组大小的。项目成果将对应用于自养新陈代谢的基因组代谢比例进行直接测试，并阐明基因组因光合代谢选择而膨胀和收缩的进化遗传机制。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The coordination between changes in metabolism and cellular structure, and between genome size and cell size, have been widely observed across all life. The nature of these relationships and their implications for generating organismal diversity remain obscure. This project will address the gap in our understanding of this potential 'rule of life' by investigating how cellular anatomy and genome size of vascular plants evolve over time in correlation with changes in photosynthetic metabolism. Researchers will combine comparative anatomical, phylogenetic, and genomic data from across the vascular plant tree of life to clarify how changes in the basic structure of a genome -its size- relates to the size of cells and, subsequently, how individual cells and entire organisms process energy. The project will train undergraduate students, including individuals from under-represented groups, and facilitate collaboration among project team members having diverse expertise, most of whom are early-career researchers. Societal benefits of the research include the potential for discovering a new, fundamental scaling law in biology as well as new pathways for developing more productive agricultural crops.This project will test whether coordination between genome size, cell size, and metabolism represents a fundamental 'rule of life' that constrains the phenotypic diversity of organisms. Researchers will use vascular plants as a model system because its lineages have shifted repeatedly among C3, C4, and CAM photosynthetic metabolisms over evolutionary time and therefore provide multiple, independent tests of the overarching hypothesis. Researchers will determine the dependence of different photosynthetic metabolisms on genome-cellular allometry across about 360 vascular plants species that encompass multiple transitions among photosynthetic pathways. Sampling will include flowering plant clades known to have many C4 and CAM transitions, including the grass and bromeliad monocot families and the eudicot order containing cacti (Caryophyllales). Genome size and anatomical traits (leaf epidermal, guard cell and vein sizes and densities) will be quantified for all species. For a subset of species, the three-dimensional structure and organization of leaf cells will be measured using microCT imaging. Researchers will then characterize how vascular plant genomes have changed in size and composition by analyzing 288 whole plant genomes. Comparative analyses will reveal genomic architecture associated with shifts in photosynthetic metabolism and will uncover how early-diverging flowering plants reduced their genome size as compared to their gymnosperm relatives. Project outcomes will provide a direct test of genome-metabolic scaling as it applies to autotrophic metabolism and elucidate the evolutionary genetic mechanisms by which genomes expand and contract in response to selection on photosynthetic metabolism.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.