GENETIC DISSECTION OF PHYTOCHROME B SIGNALLING

描述(改编自申请人摘要)： 温度、光线、风或湿度的变化，植物会改变它们的 生理学和发育。环境条件影响 致力于发展活动，如种子萌发和 开花，以及生长的调整导致形态 变异，如茎伸长、侧芽抑制(顶端 优势)，以及叶大小。植物生长和形态的这种可塑性 使人们能够通过以下方式了解植物发育的机制 研究将环境信号与 发育反应。这份提案描述了设计的实验 阐明光信号转导的分子机制。灯 几乎影响植物发展的方方面面，通过 有别于光合作用装置的信号系统。这些 系统通过动作对远红、红、蓝或紫外光做出反应 不同的光感受器。PHYB基因突变，编码 红/远红光感受器光敏色素B，引起几种发育 表型包括拉长的下胚轴、早花和 顶端优势增强。更多PhyB突变的特征 将提供有关光敏色素B的结构要求的信息 功能。筛查抑制或增强长链的突变 PhyB突变体的下胚轴表型将识别其产物的基因 在光敏色素B信号转导中的下游作用，并可能， 在其他光信号通路中。遗传学和生理学 实验将揭示由突变确定的基因的作用。 通过光来控制发展。大多数基于地图的克隆 有趣的基因座将允许分子重建途径 控制植物对环境的发育反应。 了解这些机制可能会让我们更理性地操纵 重要的农艺性状，如开花、种子、萌发和 提高作物的高度，有助于改善人类营养。 这些实验还将导致对基本机制的更全面的了解 对植物生长的影响。

DESCRIPTION (Adapted from Applicant's Abstract): When subjected to variation in temperature, light, wind, or humidity, plants alter their physiology and development. Environmental conditions influence commitment to developmental events such as seed germination and flowering, as well as adjustments of growth leading to morphological variation, such as stem elongation, lateral bud inhibition (apical dominance), and leaf size. This plasticity of plant growth and form enables one to learn about the mechanisms of plant development by studying signal transduction pathways that link environmental signals to developmental responses. This proposal describes experiments designed to elucidate molecular mechanisms of light signal transduction. Light influences virtually all aspects of plant development, through signalling system distinct from the photosynthetic apparatus. These systems respond to far-red, red, blue, or UV light through the action of distinct photoreceptors. Mutations in the PHYB gene, encoding the red/far-red photoreceptor phytochrome B, cause several developmental phenotypes including elongated hypocotyls, early flowering, and increased apical dominance. Characterization of more phyB mutations will provide information on structural requirements for phytochrome B function. Screens for mutations that suppress or enhance the long hypocotyl phenotype of a phyB mutant will identify genes whose products function downstream in phytochrome B signal transduction, and possibly, in other light signalling pathways. Genetic and physiological experiments will reveal the roles of genes identified by the mutations in control of development by light. Map-based cloning of the most interesting loci will permit molecular reconstruction of the pathways controlling plant developmental responses to the environment. Understanding these mechanisms may allow more rational manipulation of agronomically important traits such as flowering, seed, germination, and height in crop plants, contributing to improvement in human nutrition. These experiments will also lead to fuller insight into basic mechanisms of plant growth.