Genetic Networks Regulating Structure and Function of the Maize Shoot Apical Meristem

PI: Michael Scanlon（康奈尔大学）合作PI: Diane janickbuckner和Brent Buckner（杜鲁门州立大学），Gary Muehlbauer（明尼苏达大学双城分校），Thomas Owens（康奈尔大学），Patrick Schnable（爱荷华州立大学），Marja Timmermans（冷泉港实验室），Yu Jianming（堪萨斯州立大学），Zhang Xiaoyu（佐治亚大学）茎尖分生组织（shoot apical分生组织，SAM）负责植物所有地上器官的发育。SAM的结构和功能与玉米成虫的重要农艺性状有关，并受种植密度和农业环境引起的荫蔽胁迫的影响。该项目的最终目标是增加对控制SAM结构和功能的调节网络以及这些网络对环境压力的反应的理解。具体目标是：1)利用纳米尺度计算机断层扫描技术描述玉米及其近缘种SAM异速生长空间，提供SAM结构表型多样性的三维图像，鉴定与SAM结构相关的成株性状；2)鉴定SAM大小/形状异常值和SAM结构异常突变体的差异表达基因，构建SAM结构和功能相关关键基因的共表达网络；3)进行定量遗传分析，确定与SAM结构/功能变异和成虫性状相关的基因内的特定变异，并利用反向遗传方法测试40个关键基因的功能；4)分析避荫反应及其对SAM结构和功能的影响；5)利用区分玉米SAM干细胞组织区和有机源性结构域的新方案，研究SAM功能结构域在遮荫条件下的表观遗传变化。这些研究将为科学培训和原始数据的公开发布提供框架。小型文理学院杜鲁门州立大学的本科生将接受形态学和LM-RNAseq分析玉米突变体的培训。REU的学生和康奈尔大学植物生理学课程的本科生将参加生理实验。该项目将产生广泛的转录组学数据和载体构建，用于组织特异性表观遗传分析，这将提供给科学研究界。不同玉米系的分子标记和表型数据将提供给Panzea （http://www.panzea.org/）。遗传作图关联、生理避光反应数据、转录组学和表型数据将在MaizeGDB （http://www.maizegdb.org/）上进行整理，玉米茎部突变体和SAM大小变异的种子库存将通过玉米遗传合作库存中心（http://maizecoop.cropsci.uiuc.edu/）发布。

PI: Michael Scanlon (Cornell University)Co-PIs: Diane Janick-Buckner and Brent Buckner (Truman State University), Gary Muehlbauer (University of Minnesota-Twin Cities), Thomas Owens (Cornell University), Patrick Schnable (Iowa State University), Marja Timmermans (Cold Spring Harbor Laboratory), Jianming Yu (Kansas State University) and Xiaoyu Zhang (University of Georgia)Collaborators: Carolyn Lawrence (USDA-ARS/Iowa State University) and Dan Nettleton (Iowa State University)The shoot apical meristem (SAM) is responsible for development of all above ground organs in the plant. SAM structure and function correlates with agronomically-important adult traits in the maize plant, and is also affected by planting density and shade stresses induced by agricultural environments. The ultimate goal of this project is to increase understanding of the regulatory networks controlling SAM structure and function and the responses of these networks to environmental stresses. The specific objectives are to: 1) describe the SAM allometric space in maize and its relatives using nanoscale computer tomographic scanning to provide 3-dimensional images of the phenotypic diversity of SAM structure and identify adult plant traits correlated with SAM structure; 2) identify differentially expressed genes in SAM size/shape outliers and mutants with abnormal SAM structures and generate a co-expression network of key genes implicated during SAM structure and function; 3) perform quantitative genetic analyses to identify specific variations within genes that correlate with variations in SAM structure/function and adult plant traits, and test functions of 40 key genes using reverse genetic aaproaches; 4) analyze the shade avoidance response and its effects on SAM structure and function; and 5) investigate epigenetic changes of SAM functional domains in response to shade avoidance using novel protocols that distinguish the stem cell organizing regions from the organogenic domains in the maize SAM. These studies will provide the framework for scientific training and the public release of original data. Undergraduates at Truman State University, a small liberal arts institution, will be trained in morphological and LM-RNAseq analyses of maize mutants. REU students and undergraduates enrolled in Plant Physiology courses at Cornell University will participate in physiological experiments. This project will generate extensive transcriptomic data and vector constructs for tissue-specific epigenetic analyses which will be available to the scientific research community. Molecular markers and phenotypic data for diverse maize lines will be supplied to Panzea (http://www.panzea.org/). Genetic mapping associations, physiological shade-avoidance response data, transcriptomic and phenotypic data will be curated at MaizeGDB (http://www.maizegdb.org/), and seed stocks for maize shoot mutants and SAM size variants will be released through the Maize Genetics Cooperation Stock Center (http://maizecoop.cropsci.uiuc.edu/).