The origin and genetic architecture of desiccation tolerance in C4 grasses

在长期干旱期间，复活植物可以在接近完全干燥的情况下存活下来，并在恢复水分后恢复正常生长。牧草提供了人类的大部分营养，而在复活牧草中的发现可以转化为密切相关的作物物种。控制脱水耐性的遗传机制在很大程度上是未知的，但可能有助于提高作物的抗旱性。这项研究项目集中在一个经济上重要的草科植物中的复活植物。该项目涉及对农作物草和复活植物进行详细比较，以确定区分典型干旱反应和与干旱相关的基因和细胞途径。这个项目的跨学科基因组学、遗传学和进化论方面使高中生、本科生和研究生沉浸在植物科学研究的前沿。与密歇根州立大学4H儿童园合作的项目向学生和公民科学家传授干旱对农业的影响。被子植物的脱水耐性可能是通过重新连接已存在的种子干燥途径而进化的，但这种转变背后的基因和途径水平的变化尚不清楚。在这个项目中，系统水平和比较基因组学方法被用来理解C4牧草耐脱水的遗传基础。该项目的重点是来自独立的复活植物谱系的两个物种：一种是新兴的模式草Oropleum thomaeum，另一种是Eragrostis inedensis，这是一种与孤儿谷物tef(E.tef)关系密切的南非野草。首先，探索了基因和基因组复制在脱水耐受性进化中的作用，并确定了适应性进化中的基因。其次，在脱水和复水过程中，以高时间分辨率研究了转录组、表观基因组和染色质的动力学。根据这些数据集，建立了控制牧草脱水耐性的基因和调控元件的综合图谱。最后，收集了6个独立进化耐脱水的草本植物的转录组和代谢物数据，以检验收敛进化和保守的途径重排。开发了一系列教育宣传活动和教学单元，以探索植物中的干旱和水分关系。该项目的大规模数据集通过NCBI序列档案馆和CyVerse的同行评议出版物、演示文稿和沉积进行传播。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。

Resurrection plants can survive near complete drying during periods of prolonged drought and resume normal growth with the return of water. Grasses provide the bulk of human nutrition, and discoveries in resurrection grasses can be translated to closely related crop species. The genetic mechanisms controlling desiccation tolerance are largely unknown, but may be useful for improving drought tolerance in crop plants. This research project focuses on resurrection plants within an economically important grass family. The project involves a detailed comparison between crop grasses and resurrection plants in order to identify genes and cellular pathways that distinguish typical drought responses, from those associated with desiccation. The interdisciplinary genomic, genetic, and evolutionary aspects of this project immerse high school, undergraduate, and graduate students in the leading frontiers of plant science research. Projects in collaboration with the Michigan State University 4H Children's Garden teach students and citizen scientists about the impact of drought on agriculture. Desiccation tolerance in angiosperms likely evolved through rewiring pre-existing seed desiccation pathways, but the gene and pathway level changes underlying this transition are unknown. In this project, systems-level and comparative genomics approaches are used to understand the genetic basis of desiccation tolerance in C4 grasses. The project focuses on two species from independent lineages of resurrection plants: Oropetium thomaeum, an emerging model grass, and Eragrostis nindensis, a wild South African grass closely related to the orphan cereal tef (E. tef). In the first instance, the role of gene and genome duplication in the evolution of desiccation tolerance is explored and genes under adaptive evolution are identified. Second, transcriptome, epigenome, and chromatin dynamics are surveyed at high temporal resolution during the desiccation and rehydration processes. From these datasets, a comprehensive atlas of the genes and regulatory elements controlling desiccation tolerance in grasses is developed. Finally, transcriptome and metabolite data are collected from six grass species that evolved desiccation tolerance independently to test for convergent evolution and conserved pathway rewiring. A series of educational outreach activities and teaching modules are developed to explore drought and water relations in plants. Large-scale datasets from this project are disseminated through peer-reviewed publications, presentations, and deposition at the NCBI sequence archives and CyVerse.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.