Control of Embryo Development in Higher Plants

高等植物胚胎发育的控制

• 批准号: 0344753
• 负责人: John Harada
• 金额: --
• 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: 2004
• 资助国家: 美国
• 起止时间: 2004-02-15 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0344753&HistoricalAwards=false
• 关键词: Control; Embryo; Development; Higher; Plants

PI: John J. Harada December 1, 2003Control of Embryo Development in Higher Plants Page 3NSF 0344753ABSTRACTEmbryogenesis describes the period of the plant life cycle during which a single-celledzygote undergoes a series of differentiation events, resulting in the formation of a mature and metabolically quiescent embryo. Embryogenesis in higher plants consists of two conceptually distinct phases. The earliest is the morphogenesis phase during which the basic body plan of the plant is formed. This is followed by the maturation phase during which the embryo accumulates proteins and lipids, induces processes that allow them to withstand desiccation, and becomes metabolically quiescent. There are two major goals of this proposal. One objective is to understand how these two embryonic phases are coordinated. The maturation phase evolved to permit higher plants to make seeds. Given that lower plants do not undergo maturation or make seeds, it is likely that, in higher plants, the maturation phase was inserted into a continuous phase of morphogenesis. The second objective is to define the developmental processes that allow cells to change their fate and enter into an embryonic mode of development. A diversity of higher plant cell types can be induced to undergo embryogenesis. Although it is known that many of these embryos follow similar morphogenetic pathways, virtually nothing is known of the molecular processes that allow these cells to initiate embryonic programs. We will address these problems using Arabidopsis LEAFY COTYLEDON2 (LEC2). LEC2 encodes a protein that regulates the transcription of other genes and is a central regulator of embryogenesis required for processes that occur during both the morphogenesis andmaturation phases. For example, we have shown that overexpression of the LEC2 gene activates maturation processes in vegetative and reproductive organs and induces somatic embryo formation from vegetative cells. This proposal addresses the overall question of how LEC2 establishes an environment that activates the maturation program and promotes cellular competence to undergo somatic embryogenesis. An immediate objective is to identify genes directly regulated by the LEC2 transcription factor. The spectrum of genes activated and repressed should provide insight into the regulatory programs directly controlled by LEC2. A second aim is to identify other embryonic regulators that work in concert with LEC2 to discover other participants in the regulatory network controlling embryogenesis. Together, these experimental approaches should provide new insights into the control of embryo development. In addition to providing new basic knowledge about higher plant embryogenesis, information derived from these studies may be relevant to the design of strategies to manipulate seed development for applied purposes. The educational value of the project is that it will provide strong training opportunities for undergraduate, graduate students, and high schoolstudents.

PI：John J.Harada 2003年12月1日高等植物胚胎发育的控制第3页NSF 0344753ABSTRACT胚胎发生描述了植物生命周期的一段时期，在此期间，单细胞受精卵经历了一系列分化事件，导致形成成熟的代谢静止的胚胎。高等植物的胚胎发生包括两个概念上截然不同的阶段。最早的是形态发生阶段，在此期间植物的基本体面形成。紧随其后的是成熟阶段，在这一阶段，胚胎积累蛋白质和脂肪，诱导出允许它们经受干燥的过程，并在代谢上处于静止状态。这项提议有两个主要目标。一个目标是了解这两个胚胎阶段是如何协调的。成熟期的进化允许高等植物结籽。鉴于低等植物不经历成熟或结籽，在高等植物中，成熟期很可能被插入到形态发生的连续阶段。第二个目标是定义允许细胞改变其命运并进入胚胎发育模式的发育过程。多种高等植物细胞类型可以被诱导进行胚胎发生。虽然已知其中许多胚胎遵循相似的形态发生途径，但实际上对允许这些细胞启动胚胎程序的分子过程一无所知。我们将使用拟南芥LEAFY COTYLEDON2(LEC2)来解决这些问题。LEC2编码一种蛋白质，调节其他基因的转录，是胚胎发生的中央调节因子，在形态发生和成熟阶段都需要。例如，我们已经证明，LEC2基因的过表达激活了营养器官和生殖器官的成熟过程，并诱导营养细胞形成体细胞胚胎。这一建议解决了LEC2如何建立一个环境来激活成熟程序并促进细胞能力以进行体细胞胚胎发生的总体问题。一个直接的目标是识别由LEC2转录因子直接调控的基因。被激活和被抑制的基因谱应该能为LEC2直接控制的调控程序提供洞察力。第二个目标是确定与LEC2协同工作的其他胚胎调控因子，以发现控制胚胎发生的调控网络中的其他参与者。总之，这些实验方法应该会为胚胎发育的控制提供新的见解。除了提供有关高等植物胚胎发生的新的基本知识外，从这些研究中获得的信息可能与为应用目的而操纵种子发育的策略的设计相关。该项目的教育价值在于，它将为本科生、研究生和高中生提供强有力的培训机会。