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取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，其中完全成熟（分化）的细胞有能力失去其发育程序（去分化），并通过获得新的命运进入新的途径。这种能力增加了在压力条件下生存的可能性，对受损组织或器官的再生至关重要，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以形成胚胎发生细胞和胚胎（并最终形成植物）。这种营养-胚胎发生的转变可以被干扰（鼓励或抑制），并被用来识别和分析细胞发育变化的遗传因素。在这个提议中，体外胚胎发生系统将通过改变无茎杆血红蛋白和植物血红蛋白的水平而受到干扰。无SHOOTMERISTEMLESS是一种已知的细胞命运决定调节剂，而血红蛋白类调节一氧化氮水平，一氧化氮是动物和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，并将提出描述植物胚胎发生过渡的遗传模型。包括拟南芥、甘蓝型油菜（油菜）和玉米（玉米）在内的几种植物物种的利用将使结果与北美经济上重要的农作物相关。总的来说，这些结果将提供关于细胞命运获取的创新突破性知识，不仅适用于胚胎发生（和繁殖系统的改进），而且适用于需要重定向细胞行为的过程，这对于植物生产力、适应胁迫条件、预防疾病和最终存活至关重要。

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.