Regulation of Inflorescence Architecture in Maize

谷类作物，如玉米、水稻、小麦、高粱、大麦、谷子和燕麦，占世界营养的大部分。除了谷类作物，还有大约10,000种野草，覆盖了地球表面约五分之一的面积。几乎所有的草都以小穗为特征，这是一种包含花分生组织的短分支。花分生组织产生收获的种子。这些小穗在不同草类中的排列以及它们所在的分枝，反映了花序发育期间产生的分生组织的不同命运。确定决定分生组织命运的基因，并了解这些基因整合其活动的机制，将对发育生物学、进化生物学和应用遗传学和育种具有巨大的价值。发展玉米作为模式系统的前提是，来自玉米的信息应该适用于其他谷物，甚至任何其他植物。玉米与其他谷物以及玉米与野草之间的比较，将检验模型系统开发的这一基本假设。花序基因将被确定为三个不同学科的工具：草的分生组织发育调查、数量性状分析和比较生物学。表达基因的测序和表达谱将用于识别在发育最早阶段表达的基因子集，以及与选定突变体中特定分生组织类型的增殖相关的基因子集。这些基因的功能将通过遗传和定位来确定。花序基因的图谱位置将提供与数量性状以及玉米和其他禾本科植物突变的联系。一组选定的基因将通过反向遗传学进行突变，以确定它们在花序发育中的功能。这些基因的一个子集也将在其他谷物和野草中进行研究。这些基因是否随着进化时间的推移而被修改，以及它们在其他禾本科植物中的功能是否与它们在玉米中的功能相同，将被确定。这些比较将为研究6000万年来草的进化和多样性提供有价值的数据集。

The cereal crops, such as maize, rice, wheat, sorghum, barley, millet, and oats, account for the majority of world's nutrition. In addition to the cereal crops, there are approximately 10,000 species of wild grasses, which cover about 1/5 of the earth's land surface. Nearly all grasses are characterized by the spikelet, a short branch that contains floral meristems. Floral meristems produce the seeds that are harvested. The arrangement of these spikelets in different grasses, and the branches on which they are borne, reflects differing fates of the meristems produced during inflorescence development. Identifying the genes that determine meristem fates and understanding the mechanism by which these genes integrate their activities would be of immense value for developmental biology, evolutionary biology, and applied genetics and breeding. Development of maize as a model system assumes that information from maize should be applicable to other cereals, and indeed to any other plant. Comparisons between maize and the other cereals, and between maize and wild grasses, will test this basic assumption of model system development. Inflorescence genes will be identified that will serve as tools for three different disciplines: investigation of meristem development, quantitative trait analysis, and comparative biology in the grasses. Sequencing of expressed genes and expression profiling will be used to identify a subset of genes that are expressed at the earliest stages of development, and that correlate with the proliferation of specific meristem types in selected mutants. The function of these genes will be determined through genetics and mapping. Map positions of the inflorescence genes will provide a link to quantitative traits, and to mutations in maize and other grasses. A selected group of genes will be mutated by reverse genetics to determine their function in inflorescence development. A subset of the genes will also be studied in other cereals and wild grasses. Whether these genes have been modified over evolutionary time and whether they function in other grasses the same way as they do in maize will be determined. These comparisons will provide a valuable data set for the study of evolution and diversity across 60 million years of grass evolution.