RESEARCH-PGR: Genome-Wide Dissection of Leaf Angle Variation Across the Canopy in Maize

植物建筑是植物主体的三维组织形式。除了分枝模式外，叶片和开花器官的大小、形状和位置构成了地上植物的结构。叶子角度是叶子和植物茎之间的角度。在田间种植的作物中，叶角度是决定冠层叶面积、光捕获量和产量的关键因素。技术进步使得以高通量方式从田间种植的植物中获得测量数据、进行组织特异性基因表达分析以及精确编辑基因以进行功能表征成为可能。为了利用这些令人兴奋的进展，组建了一个跨学科的团队来研究玉米的叶角度变化，玉米是一种具有重要经济和社会意义的优秀模式作物。其长期目标是丰富对玉米冠层叶角度变异的遗传控制的基本了解，并为持续作物改良提供对植物结构遗传操纵的机械性见解。在该项目中将研究与教育相结合，将允许交叉培训具有发育遗传学、基因组学、生物技术、育种和农业工程知识的下一代科学家。作为将生物学和农业与学校花园和儿童文学联系起来的极好切入点，叶角将成为K-12教师培训证书讲习班的关键组成部分，该讲习班将帮助学生学习植物生物学、驯化、农业和作物改良。叶角是植物建筑学的战略组成部分，也是植物研究的一个重要领域，它将植物发育机制的基础研究与植物育种努力相结合，以实现可持续农业生产。通过密植获得更高的农艺产量的长期选择已经产生了叶片直立的优良玉米杂交种。然而，对叶片角度变异的遗传机制仍缺乏全面的了解。由于测量的困难，在大规模的遗传研究中，叶片角度通常是在每株植物的单个叶片上测量的。但在同一植株的不同叶片中观察到跨越冠层的叶角变异，并且不同的自交系对于这种“株内，叶角变异”的表型是多态的。在这个项目中，将使用高通量表型系统(PhenoBot)在全基因组范围内识别冠层中叶角度变异的基因，以量化不同节处的多个叶角，以便进行遗传分析。转录分析将通过激光显微切割RNA测序进行，以检查树冠上潜在的叶角度变化的基因和途径。根据文献中的已知基因列表和新鉴定的基因，将通过使用基于CRISPR的工具生成编辑的玉米植株来对这些基因进行功能验证和表征。将开发不同玉米自交系的年级级文本集和配套种子，用于在校园内创建教学花园。将开发一个工作坊形式的证书计划，以帮助K-12教师将教学园区整合到他们的课程中。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。

Plant architecture is the three-dimensional organization of the plant body. In addition to branching patterns, the size, shape, and position of leaves and flowering organs comprise the above-ground plant architecture. Leaf angle is the angle between the leaf and the plant stem. In cultivated crops where a very large numbers of plants are packed into the field, leaf angle is a key determinant of the overall canopy leaf area, light capture, and yield of a given plant population. Technological advances have made it possible to obtain measurements from field-grown plants in a high-throughput fashion, to conduct tissue-specific gene expression analysis, and to precisely edit genes for functional characterization. To capitalize these exciting advances, an interdisciplinary team was assembled to study leaf angle variation across the canopy in maize, an excellent model crop of economic and societal importance. The long-term goal is to enrich the fundamental understanding of the genetic control of leaf angle variation across the canopy in maize and to provide mechanistic insights into genetic manipulation of plant architecture for continued crop improvement. Integration of research with education within the project will permit cross-training of the next generation of scientists with knowledge of developmental genetics, genomics, biotechnology, breeding, and agricultural engineering. As an excellent entry point to connect biology and agriculture with school gardens and children’s literature, leaf angle will be a key component of a K-12 teacher training certificate workshop that will be developed to help students learn about plant biology, domestication, agriculture, and crop improvement.Leaf angle is a strategic component of plant architecture, and an important area of plant research that interconnects fundamental research on the mechanisms of plant development with plant breeding efforts for sustainable agricultural production. Long-term selection for greater agronomic yield by dense planting has generated superior maize hybrids with upright leaf angle. However, a comprehensive understanding of the genetic mechanisms underlying leaf angle variation is still lacking. Due to the measurement difficulties, leaf angle is typically measured on a single leaf per plant in large-scale genetic studies. But leaf angle variation across the canopy is observed among different leaves of the same plant, and diverse inbreds are polymorphic for this “within-plant, leaf angle variation” phenotype. In this project, genome-wide identification of genes underlying leaf angle variation across the canopy will be conducted using a high throughput phenotyping system (PhenoBot) to quantify multiple leaf angles at different nodes for genetic analyses. Transcriptomic analyses will be conducted through laser-microdissection RNA sequencing to examine genes and pathways underlying leaf angle variation across the canopy. With a list of known genes from the literature and newly identified genes, functional validation and characterization of these genes will be carried out by generating edited maize plants with CRISPR-based tools. Grade-level text sets and accompanying seeds of diverse maize inbreds will be developed for the creation of teaching gardens on school grounds. A certificate program in the form of a workshop will be developed to help K-12 teachers integrate the teaching garden into their curriculum.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.