Mechanisms Controlling Hormone-Mediated Plant Growth in Response to the Environment

项目摘要/摘要 生物体改变其生长和发育以适应其生长和发育的机制 周围环境在很大程度上是未知的。植物表现出巨大的表型可塑性，因为 大多数植物器官直到种子萌发后才出现，从而使器官的大小和形状得到优化 对当地环境的影响。因为植物是固着的和进行光合作用的，所以它们特别适应它们的 光环境。光影响着每一个发育转变，从种子萌发到开花，有 尤其是对幼苗的形态发生有显著影响。在这个发展阶段，光可以 在几个小时内改变数千个基因的表达。光信号不是自主行为，而是 结合温度的季节/日变化和固有程序来指定正确的空间和 基因表达、细胞器发育和细胞分化的时间调控。 拟议的研究旨在回答以下问题：(1)什么是关键的信号通路和 将来自环境的信息转化为生长速度的变化或启动 开花？(2)是否有多种途径达到相同的反应？(3)在没有中枢神经系统的情况下， 多细胞生物如何整合空间和时间上分离的大量信号 经常发出相互矛盾的信息？(4)我们能开发出植物生长的预测模型吗？这些问题将 用植物生命周期的三个阶段来处理，这三个阶段已经被充分研究并被认为对 环境输入，即遮荫诱导的生长激活，光照强度诱导的生长抑制， 和遮荫诱导的早花。在这些背景下，我们会问一组不同的转录反应 是由少量信号通路激活产生的。这些研究的结果将是 增加了对特定激素信号转导途径的遗传传感器的使用。这些数据将提供 深入分析荷尔蒙对非生物胁迫组合的反应。 植物对光和其他环境参数的不同反应提供了一个独特的模型 用于理解调节表型可塑性的信号通路的系统。相当大的基因 每条单独信号通路可用的资源使这些实验变得可行和及时。我们的 这些努力应该大大有助于了解复杂的信号转导网络和我们正在出现的 了解它们如何在多个王国中以空间和时间方式调节新陈代谢。

PROJECT SUMMARY/ABSTRACT The mechanisms by which organisms alter their growth and development in response to changes in their ambient environment are largely unknown. Plants exhibit an enormous array of phenotypic plasticity because most plant organs do not arise until after the seed germinates, allowing organ size and shape to be optimized to the local environment. Because plants are sessile and photosynthetic, they are especially attuned to their light environment. Light influences every developmental transition, from seed germination to flowering, having particularly dramatic effects on the morphogenesis of seedlings. During this stage of development, light can alter the expression of thousands of genes within a few hours. Light signals do not act autonomously, but are integrated with seasonal/diurnal changes in temperature and intrinsic programs to specify correct spatial and temporal regulation of gene expression, organelle development, and cellular differentiation. The proposed studies aim to answer the following questions: (1) What are the key signaling pathways and mechanisms that translate information from the environment into changes in growth rate or the initiation of flowering? (2) Are there multiple routes to the same response? (3) In the absence of a central nervous system, how do multicellular organisms integrate a multitude of signals that are spatially and temporally separated and often send conflicting messages? (4) Can we develop predictive models of plant growth? These questions will be addressed using three stages of the plant life cycle that are well studied and known to be highly sensitive to environmental input, namely shade-induced activation of growth, light intensity-induced inhibition of growth, and shade-induced early flowering. In these contexts we will ask how a diverse set of transcriptional responses is generated by the activation of a small number of signaling pathways. The resolution of the studies will be increased using genetic sensors for specific hormone signal transduction pathways. These data will provide an in-depth analysis of hormonal responses to combinations of abiotic stresses. The diverse responses that plants exhibit to light and other environmental parameters provide a unique model system for understanding signaling pathways that regulate phenotypic plasticity. The considerable genetic resources available for each individual signaling pathway make these experiments feasible and timely. Our efforts should contribute significantly to knowledge of complex signal transduction networks and our emerging understanding of how they modulate metabolism in a spatial and temporal manner in multiple kingdoms.