Regulation of in vitro embryogenesis

了解细胞在不断变化的环境条件下如何表现和采用特定的发育命运是动植物生物学中的一个基本问题。这一概念在植物中得到了最好的例证，在植物中，完全成熟的(分化的)细胞有能力失去它们的发育程序(去分化)，并通过获得新的命运而走上新的道路。这种能力增加了在应激条件下存活的可能性，对于再生受损的组织或器官至关重要，将使用体外胚胎发生作为模型系统进行研究。在体外胚胎发生过程中，具有营养发育命运的细胞可以通过简单的化学操作重新编程形成胚性细胞和胚胎(最终形成植物)。 这种营养-胚性转变可以被干扰(鼓励或抑制)，并被用来识别和分析支持细胞发育变化的遗传因素。在这项提议中，通过改变SHOTMERISTEMLESS和植物血红蛋白的水平来扰乱体外胚胎发生系统。SHOOTMERISTEMLESS是细胞命运决定的已知调节因子，而血红蛋白调节一氧化氮的水平，一氧化氮是动植物中普遍存在的能够重新编程细胞行为的信号分子。尖端技术将定义伴随这些扰动的结构、生理和分子变化，并将提出描绘营养-胚胎发育转变的遗传模型。对拟南芥、甘蓝型油菜和玉米等几种植物的利用将使研究结果与北美重要的经济作物有关。总而言之，这些结果将提供关于细胞命运获得的创新突破性知识，不仅适用于胚胎发生(和繁殖系统的改进)，而且适用于需要改变细胞行为的过程，这对植物生产力、适应胁迫条件、预防疾病和最终生存至关重要。

Understanding how cells behave and adopt specific developmental fates under changing environmental conditions is a fundamental question in animal and plant biology. The concept is best exemplified in plants where fully mature (differentiated) cells have the ability to lose their developmental program (de-differentiate) and embark into new pathways through the acquisition of novel fates. This capacity, which increases possibilities of survival during stress conditions and is vital for regenerating damaged tissues or organs, will be studied using in vitro embryogenesis as a model system. During in vitro embryogenesis, cells with a vegetative developmental fate can be reprogrammed to form embryogenic cells and embryos (and eventually plants) by simple chemical manipulations. This vegetative-embryogenic transition can be perturbed (encouraged or repressed) and exploited to identify and analyze the genetic elements underpinning changes in cell development. In this proposal, the in vitro embryogenesis system will be perturbed by altering the levels of SHOOTMERISTEMLESS and plant HEMOGLOBINS. SHOOTMERISTEMLESS is a known regulator of cell fate decision while HEMOGLOBINS regulate the levels of nitric oxide, a ubiquitous signal molecule in animals and plants able to reprogram cell behavior. Cutting edge techniques will define structural, physiological, and molecular changes accompanying these perturbations and will propose genetic models delineating the vegetative-embryogenic transition. The utilization of several plant species including Arabidopsis, Brassica napus (canola) and maize (corn) will make the results relevant for economically important agricultural crops in North America. Collectively these results will provide innovative breakthrough knowledge on cell fate acquisition applicable not only to embryogenesis (and the improvement of propagation systems), but to processes requiring a redirection of cell behavior which are crucial for plant productivity, adaptation to stress conditions, prevention of diseases and ultimately survival.