Patterns and Mechanisms of Ovule Diversification

胚珠多样化的模式和机制

• 批准号: 9983354
• 负责人: Charles Gasser
• 金额: $ 35.68万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9983354&HistoricalAwards=false
• 关键词: Patterns; Mechanisms; Ovule; Diversification

As the developmental precursors to seeds, ovules are a defining feature ofseed plants and play essential roles in their sexual reproduction. Amongangiosperms, the dominant group of seed plants, ovules are diverse,exhibiting differences in the number of integuments (external sheathingstructures), and in the orientation of the micropyle (the opening in theinteguments which facilitates fertilization). Ovule diversity has beeninvaluable in evolutionary studies of angiosperms, and ovule developmenthas become a useful model for studies on genetic regulation of plantmorphogenesis. An interdisciplinary approach will be used to characterize the historicalpatterns of ovule evolution and its molecular genetic basis. Ovulecharacteristics will be plotted onto the best available phylogenies forangiosperms to clarify transitions between primitive and derived ovulefeatures. Species having either primitive or derived ovule features willbe selected for phenotypic and molecular genetic characterization.Molecular genetic analysis of the basis of changes in integument number andmicropyle orientation will be accomplished through analysis of orthologs ofINO, a gene which regulates these processes in Arabidopsis and which isspecifically expressed in the outer integument. Isolation of INO orthologsfrom key species, and characterization of expression patterns, will enablethe formulation and testing of hypotheses on the molecular genetic changesunderlying ovule diversification. To facilitate future studies on ovule diversification, we will also isolateATS, a gene required for developmental separation of outer and innerinteguments in Arabidopsis. Completion of the proposed work will provide insights into the regulationof plant development, ovule diversification, and their interrelationship.

作为种子的发育前体，胚珠是种子植物的一个重要特征，并在有性生殖中发挥着重要作用。 被子植物是种子植物的主要类群，胚珠种类繁多，珠被（外鞘结构）的数量和珠孔（珠被上有利于受精的开口）的方向都有差异。 胚珠多样性在被子植物进化研究中具有重要价值，胚珠发育已成为研究植物形态发生遗传调控的有用模型。 将采用跨学科的方法来描述胚珠进化的历史模式及其分子遗传学基础。 胚珠特征将被绘制到被子植物的最佳可获得的胚珠发生上，以澄清原始胚珠特征和衍生胚珠特征之间的过渡。 将选择具有原始或衍生胚珠特征的物种进行表型和分子遗传学表征。珠被数量和珠孔方向变化基础的分子遗传学分析将通过分析INO的直系同源物来完成，INO是拟南芥中调节这些过程的基因，并且在外珠被中特异表达。 从关键物种中分离INO直向同源物，并对表达模式进行表征，将使关于胚珠多样化的分子遗传变化的假设得以制定和检验。 为了便于今后胚珠分化的研究，我们还将分离拟南芥中外珠被和内珠被发育分离所需的基因ATS。 这项工作的完成将为植物发育、胚珠多样化及其相互关系的调节提供新的见解。