Shoot apical meristem ontogenesis in vivo and in vitro

*正如已故的伊恩·苏塞克斯教授在他的评论(Cell 56：225，)中所说，“分生组织造就了植物”。顶端分生组织是植物所有细胞的母体。它们负责初级植物体内组织和器官的形成。没有正常运作的AM，陆地植物就不会存在。虽然最近在理解AM在植物正常发育过程中的形成、维持和功能方面取得了进展，但我们仍然不完全了解AM是如何在胚胎发生期间启动的。植物组织培养和微繁殖是植物商品化生产的重要途径。为了获得成功，AM在新再生植株中的形成是必须的。此外，我们对AM在体外微繁殖植物中的启动的了解甚至比体内的研究更有限。兰花是一种特别重要的商业植物。与其他开花植物不同，兰花AM在胚胎发育过程中不存在；相反，它们在种子萌发后启动。这就提出了这样的问题：为什么兰花在分生组织起始时选择这种策略，以及分生组织基因调控导致分生组织形成延迟的机制(S)是什么？由于这项研究的重点是对植物发育至关重要的中心结构，所以这项研究对所有对植物生长和发育感兴趣的生物学家都很重要。本研究的总体目标是以拟南芥胚胎为外植体，以在体为实验系统，以蝴蝶兰、蝴蝶兰、发育中的胚胎和原球茎为实验系统，提供对茎顶端分生组织个体发育的机制的了解。我们预计，利用这些实验系统，我们可以揭开分生组织启动和相关调控机制(S)中的关键事件。除了理论上的贡献，我们将能够设计和/或推荐植物微繁殖的新方案。关于体内和体外分生组织形成的知识是植物生物技术应用的基础。这些信息将使对植物生长和发育感兴趣的普通人和科学家以及对植物生产感兴趣的国内外商业种植者受益。如果不定芽再生得到保证，这将在转化研究和转基因植物的产生方面取得更多成功。近年来的气候变化给作物生产和产量带来了不确定性。我们在微繁殖植物上保证新梢产量的能力将确保植物产量和提高产量。更好地了解兰花分生组织的形成将有助于保护物种免受自然生境的侵蚀，因为顶端分生组织的形成是进一步生长和发展的先决条件。这一积极的结果也将有助于这一独特的开花植物组的商业化。

***As the Late Professor Ian Sussex stated in his review (Cell 56: 225, 1989), “The meristems make the plant”. Apical meristems (AMs) are the mother of all cells in plants. They are responsible for the formation of tissues and organs of the primary plant body. Without properly functioning AMs, land plants will not exist. Although recent advances have been made in our understanding of the formation, maintenance, and function of AMs during normal plant development, we still do not fully understand how they are initiated during embryogenesis. Tissue culture and micropropagation of plants are important approaches in commercial plant production. To be successful, AM formation is a must in the newly regenerated plants. Moreover, our understanding of AM initiation from in vitro micropropagated plants is even more limited than in vivo studies. One particularly commercially important plant is the orchid. Unlike other flowering plants, orchid AMs are absent during embryo development; instead, they are initiated after seed germination. This begs the questions as to why orchids choose this strategy in meristem initiation and what is the mechanism(s) of meristem gene regulation leading to the delay in meristem formation. Since this research program focuses on a central structure which is key to plant development, this research is important to all biologists interested in plant growth and development.******The overall goal of this research program is to provide a mechanistic understanding of shoot apical meristem ontogeny in vitro using Arabidopsis embryos as explants and in vivo using the moth orchid, Phalaenopsis, developing embryos and protocorms as our experimental systems. We anticipate that we can unravel key events in meristem initiation and the associated regulatory mechanism(s) using these experimental systems. Besides theoretical contributions, we will be able to devise and/or recommend new protocols for plant micropropagation. ******The knowledge concerning meristem formation in vivo and in vitro is the foundation for plant biotechnology applications. The information will benefit both layman and scientists interested in plant growth and development and also to commercial growers nationally and internationally, interested in plant production. If shoot regeneration is guaranteed, this will lead to more successes in transformation studies and the generation of genetically modified plants. Climate change in recent years has brought uncertainty in crop production and yield. Our ability to guarantee shoot production in micropropagated plants will ensure plant production and improve yield. A better understanding of meristem formation in orchids will help in the conservation of species from natural habitat erosion, as apical meristem formation is a prerequisite for further growth and development. This positive outcome will also assist in the commercialization of this unique group of flowering plants.