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

植物结构是植物体的三维组织。除了分支模式外，叶子和开花器官的大小、形状和位置也构成了地上植物的结构。叶角是指植物叶片与茎的夹角。在种植大量植物的作物中，叶片角度是决定总冠层叶面积、光捕获和给定植物种群产量的关键因素。技术的进步使得人们能够以高通量的方式从田间种植的植物中获得测量结果，进行组织特异性基因表达分析，并精确编辑基因以进行功能表征。为了利用这些令人兴奋的进展，一个跨学科的团队被召集起来研究玉米的叶片角度在冠层上的变化，玉米是一种具有经济和社会重要性的优秀模式作物。长期目标是丰富对玉米冠层叶片角度变异遗传控制的基本认识，并为植物结构的遗传操纵提供机制见解，以促进作物的持续改良。该项目将研究与教育相结合，可以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一个极好的切入点，《叶子角度》将成为K-12教师培训证书研讨会的一个关键组成部分，该研讨会将帮助学生学习植物生物学、驯化、农业和作物改良。叶片角度是植物结构的重要组成部分，是植物发育机制的基础研究与植物育种工作相互联系的重要研究领域，有利于农业可持续生产。为提高农艺产量，通过密植的长期选择，产生了叶角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认识。由于测量困难，在大规模遗传研究中，叶片角度通常是在每株植物的单叶上测量的。但同一植株不同叶片间存在冠层上的叶角变异，且这种“株内叶角变异”表型在不同自交系中存在多态性。在本项目中，将使用高通量表型系统（PhenoBot）对冠层叶片角度变化的基因进行全基因组鉴定，以量化不同节点的多个叶片角度进行遗传分析。转录组学分析将通过激光显微解剖RNA测序来研究冠层叶片角度变化的基因和途径。利用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的工具生成编辑过的玉米植株，对这些基因进行功能验证和表征。将开发年级水平的文本集和随附的各种玉米近交系种子，用于在学校场地上创建教学花园。将开发一个以研讨会形式的证书课程，以帮助K-12教师将教学花园融入他们的课程。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。

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.