Genetic Mechanisms Regulating Inflorescence Architecture in Maize and other Cereals

Sarah Hake，加州大学伯克利分校，P.I.David Jackson，冷泉港，密苏里州大学圣路易斯分校，Torbert Rocheford，伊利诺伊大学香槟分校，Robert Schmidt，加州大学圣地亚哥分校，Erik Vollbrecht，爱荷华州立大学，CoP.I.Vollbrecht，爱荷华州立大学，Co-P.I.Volker Brendel，爱荷华州立大学，资深个人Richard Johnson，伊利诺伊大学，合作者理查德·约翰逊。一个长期目标是了解禾本科植物花序形态多样化的遗传基础，禾本科植物约有10,000个物种，包括主要的谷类作物。花序是一个开花的结构，并保存种子(谷物)。植物花序构型的变化在很大程度上取决于分生组织的活动，分生组织是一小群干细胞，它们使自己永久化并形成器官。草花序之间的多样性尤其显著，这是由于在整个花序发育过程中产生的几个不同分生组织的特性和确定性的差异造成的。这种多样性具有重要的农业意义，因为花粉和种子是在花序的分枝上产生的。在他们之前的资助中，研究人员克隆了一些关键基因，这些基因调控花序发育过程中的关键步骤，从分生组织的启动和组织到分生组织的分生组织模式和分生组织的决定。目前项目的具体目标是确定这些基因如何适应更大的遗传网络，并确定玉米和其他牧草网络的分歧和保守性。该项目利用新的高分辨率玉米作图资源和预期的基因组序列，对数量性状基因座(QTL)进行精细定位，并利用关联分析将基因型与表型联系起来。这项研究将解决如下问题：为什么玉米穗和雄穗如此不同，但却来自相似的原基；哪些基因区分了牧草不同的分枝结构；花序结构基因的变异如何调节玉米自交系的不同结构。这些问题的答案将为谷物和其他草种生殖生物学的遗传学研究奠定基础。在这个项目中，将识别整合穗和雄穗发育早期步骤的关键基因和基因网络，并将发现那些构成其独特表型的基因和基因网络。这些将作为发育生物学、进化生物学、应用遗传学和育种研究的工具，与玉米杂交制种和作物改良具有明显的相关性。暑期推广计划的目标是接触到大量的高中生和本科生，并提供田间和实验室遗传学和基因组学的实践经验。项目结果将在明确的自交系背景下确定，并将通过玉米遗传资源中心(http://maizecoop.cropsci.uiuc.edu/).)提供项目数据将通过MaizeGDB(http://www.maizegdb.org/).)提供

Sarah Hake, University of California, Berkeley, P.I.David Jackson, Cold Spring Harbor, Co-P.I.Elizabeth Kellogg, University of Missouri, St. Louis, Co-P.I.Torbert Rocheford, University of Illinois, Champaign, Co-P.I.Robert Schmidt, University of California, San Diego, Co-P.I.Erik Vollbrecht, Iowa State University, Co-P.I.Volker Brendel, Iowa State University, Senior PersonnelRichard Johnson, University of Illinois, CooperatorThe overall goals of this project is to uncover the network of genetic interactions responsible for maize inflorescence development. A longterm goal is to understand the genetic basis for diversification in inflorescence morphology in grasses, a group of about 10,000 plant species including major cereal crops. The inflorescence is a flowering structure and hold seeds (grains in case of cereals). The variation in architecture of plant inflorescences is largely determined by the activity of meristems, small groups of stem cells that perpetuate themselves and give rise to organs. The diversity among grass inflorescences is particularly striking and results from variation in the identity and determinacy of several distinct meristems produced throughout inflorescence development. This diversity has important agricultural implications as pollen and seeds are produced on branches of the inflorescence. In their previous grant, the investigators cloned a number of key genes that regulate critical steps in the pathway of inflorescence development, from meristem initiation and organization to patterns of branching and meristem determinacy. The specific objective of the current project is to determine how these genes fit into a larger genetic network and to determine divergence and conservation of networks in maize and other grasses. The project takes advantage of new high resolution maize mapping resources and the expected genome sequence to fine map quantitative trait loci (QTL) and use association analysis to link genotype with phenotype. The research will address questions such as why the maize ear and tassel are so distinct yet arise from similar primordia, what are the genes that differentiate diverse branching structures of the grasses, and how variation in inflorescence architecture genes regulates the diverse architectures of maize inbred lines. Answers to these questions will establish a foundation for genetic studies of reproductive biology in cereals and other grass species. In this project, key genes and gene networks that integrate the early steps in ear and tassel development will be identified and those that underlie their distinct phenotypes will be uncovered. These will serve as tools for research in developmental biology, evolutionary biology, applied genetics and breeding, with obvious relevance to maize hybrid seed production and crop improvement. The summer outreach program aims to reach a large number of high school students and undergraduates and provide hands-on experience in field and laboratory genetics and genomics.Access to project outcomesThe mutants to be identified will be in defined inbred backgrounds and will be made available through the Maize Genetics Stock Center (http://maizecoop.cropsci.uiuc.edu/). Project data will be made available through MaizeGDB (http://www.maizegdb.org/).