Proximal Distal Patterning During Maize Leaf Development

知识价值。玉米叶片由上部光合叶片组成，叶片在叶舌区域与下部鞘分离。去除或改变叶舌区域的突变减少了叶片相对于鞘的角度，导致叶片直立伸展。叶舌区因此有助于确定植物的形状，了解结构如何发展将为作物改良提供新的工具。舌瓣区域在发育早期可见于一个受限的部位，称为舌瓣前带，最初的标志是细胞分裂增加，细胞扩增和局部基因表达。生长素载体蛋白的荧光标记也定位于舌瓣前带，提示激素信号在建立该位点中的作用。为了了解舌瓣发育的机制，将使用一系列荧光标记来绘制早期舌瓣发育过程中表达的序列变化。唇瓣前区域的基因表达谱将使用激光捕获显微解剖和RNA测序来生成。沿着叶轴的三个区域将被捕获，包括舌叶前带本身，毗邻的叶片和对应的鞘组织。将正常植物与突变植物进行比较，以确定当舌叶生长改变时基因组水平上的表达变化。生物信息学工具将用于从这些表达目录中选择候选基因进行进一步研究。所选基因将通过qRT-PCR进行验证，并通过全株原位杂交研究其表达模式。这项研究将确定形成叶舌所需的顺序和潜在的相互作用因素，并将为操纵叶片形状提供新的遗传工具。更广泛的影响。叶片角是玉米等粮食作物的重要农艺性状。由于叶叶结构的变化，直立叶片较多的植物，如果能在较少的空间内进行最佳的光合作用，可能会有更高的产量。玉米舌瓣突变体也是教授学生发育遗传学和基因组学的绝佳工具。该项目将专门为社区学院的学生提供暑期研究机会，并将与怀俄明大学（UW）建立的教育项目合作开发社区学院的教学模块。教学模块将使用西澳大学科学数学教学中心开发的方法进行评估，并通过西澳大学传播给参与的社区学院。研究数据和教学模块将发布在项目网站上，并向研究界和公众提供。

Intellectual Merit. Maize leaves consist of an upper photosynthetic blade separated at the ligule region from a lower enclosing sheath. Mutations that remove or alter the ligule region reduce the angle of the blade relative to the sheath, causing the leaves to extend upright. The ligule region thus helps to determine plant shape, and understanding how the structure develops will provide new tools for crop improvement. The ligule region is visible early in development at a restricted site, called a pre-ligule band, marked initially by increased cell division, cell expansion and localized gene expression. A fluorescent marker for an auxin carrier protein also localizes to the pre-ligule band, suggesting a role for hormone signaling in establishing the site. To understand the mechanism of ligule development, a collection of fluorescent markers will be used to map sequential changes in expression during early ligule development. Gene expression profiles in the pre-ligule region will be generated using laser capture microdissection followed by RNA sequencing. Three regions along the leaf axis will be captured, including the pre-ligule band itself, adjoining blade and subtending sheath tissue. Normal plants will be compared to mutants to identify expression changes on a genomic level when ligule growth is altered. Bioinformatic tools will be used to select candidate genes from these expression catalogs for further study. The selected genes will be validated by qRT-PCR, and their expression patterns studied by whole mount in situ hybridization. This research will identify the sequential and potentially interacting factors needed to make a ligule and will offer new genetic tools for manipulating leaf shape. Broader impacts. Leaf blade angle is an important agronomic trait in grain crops, such as maize. Plants with more upright leaves, caused by changes in ligule structure, may have higher crop yield if optimal photosynthesis can occur in less space. Maize ligule mutants are also excellent tools for teaching students about developmental genetics and genomics. The project will provide summer research opportunities specifically to Community College students and will develop Community College teaching modules in collaboration with education programs established at the University of Wyoming (UW). The teaching modules will be assessed using methods developed at the Science Math Teaching Center at UW and disseminated through UW to participating Community Colleges. Research data and teaching modules will be posted at a project website and made available to the research community and general public.