Cell-specific transcriptional responses to environmental stress in Arabidopsis

描述(由申请人提供)：环境胁迫部分通过影响转录因子(TF)网络来塑造植物的发育。理解这些网络以及它们如何对外界刺激做出反应，是理解动物和植物发育的关键。我们的长期目标是1)了解环境信号是如何被感知并转化为植物根的发育变化的，2)建立在各种环境胁迫下根转录网络的概况，3)利用这些信息产生系统生物学方法来理解植物的发育，并寻找植物和动物转录网络之间的广泛共性。我们将重点研究铝(Al)毒性，以研究环境胁迫、根发育和转录网络之间的关系。铝的毒性水平抑制了初生根的生长，经常在酸性土壤中发现。由于转录因子在植物发育过程中是必不可少的，而植物发育过程又受到环境的影响，因此它们的表达应该随着外界胁迫的变化而改变。因此，我们假设铝通过影响参与细胞增殖和伸长的转录因子的表达和/或蛋白质定位来抑制根的伸长，细胞增殖和伸长是器官生长的两个主要过程。我们的实验室已经开发了一种基于对荧光标记的细胞类型进行排序的协议，以检查细胞特定分辨率下的全球基因表达，并使用它来开发非胁迫条件下的拟南芥根表达图谱。我们将利用这种方法来理解Tf对铝胁迫的反应，以及这种反应是如何导致拟南芥器官生长和发育受到抑制的。我们的具体目标是：1.用荧光标记的细胞系鉴定6种不同类型的根细胞对铝的响应的形态变化。虽然铝的全根效应已经被研究，但铝对特定的根细胞类型的影响还不是很清楚。2.利用基因芯片技术筛选出受铝胁迫影响的拟南芥根全长基因。为了确定受压力影响最大的潜在组织类型，我们将把这里确定的基因与我们在非胁迫条件下创建的根表达图谱进行交叉参考。3.对受铝影响最大的组织类型进行详细的细胞特异性微阵列分析，并确定变化最大的组织因子。4.通过突变体鉴定，阐明所选择的Tf在铝毒害和根生长中的作用。5.检测对铝敏感性不同的拟南芥材料中Tf的表达。尽管植物和动物的发育过程明显不同，但必须解决相同的基本问题才能产生成功的多细胞有机体。因此，生命发展所经历的复杂的相互作用很可能遵循大致平行的模式。

DESCRIPTION (provided by applicant): Environmental stress shapes plant development in part by affecting transcription factor (TF) networks. Comprehending these networks and how they respond to external stimuli is key to understanding both animal and plant development. Our long-term goals are 1) to understand how environmental signals are perceived and translated into developmental changes in the plant root, 2) to develop a profile of the root transcription network under various environmental stresses, and 3) to use this information in generating a systems biology approach towards understanding plant development and to look for broad commonalities between plant and animal transcription networks. We will focus on aluminum (Al) toxicity to study the relationship between environmental stress, root development, and transcription networks. Toxic levels of Al inhibit growth of the primary root, and are often found in acidic soils. Since TFs are essential to plant developmental processes, which are in turn affected by the environment, their expression should change in response to external stress. Thus, we hypothesize that Al inhibits root elongation by affecting the expression and/or protein localization of transcription factors involved in cell proliferation and elongation, two of the major processes in organ growth. Our lab has developed a protocol based on sorting fluorescently marked cell types to examine global gene expression at cell-specific resolution, and used it to develop an Arabidopsis root expression map under unstressed conditions. We will apply this method to understand TF responses to Al stress, and how such responses result in the inhibition of organ growth and development in Arabidopsis. Our specific aims are to: 1. Identify morphological changes in 6 different root cell types in response to Al with fluorescently marked cell lines. Although whole root effects of Al have been studied, effects of Al on specific root cell types are not well known. 2. Identify the set of genes affected by Al stress in the whole Arabidopsis root with microarray analysis. To identify potential tissue types most strongly affected by the stress, we will cross reference genes identified here with our root expression map created under unstressed conditions. 3. Perform detailed cell-specific microarray analysis on tissue types most affected by Al and identify the most altered TFs. 4. Clarify the role of selected TFs in Al toxicity and root growth by mutant characterization. 5. Examine selected TF expression in Arabidopsis accessions with different sensitivities to Al. Though plant and animal developmental processes are clearly different, the same basic problems had to be solved to result in a successful multicellular organism. The complex interactions through which life develops are thus likely to follow broadly parallel patterns.