Elucidating how drought stress reprograms genome activity

项目摘要 生物体进化为在一个沿着多个维度变化的环境中生存和繁殖。作为 因此，基因组通过基因表达的重大改变对环境压力作出反应。在 真核生物，环境和发育信号通过染色质与基因组相互作用， 了解染色质结构在应激依赖基因表达程序激活中的作用 是至关重要的.因此，我们需要新的研究来剖析控制压力反应的机制， 在有机体生理学上有很好的基础。植物为解决这一问题提供了独特的机会。支持 作为一种固着的生活方式，植物进化出了复杂的机制来调整它们的生长和生理， 环境挑战，如干旱，对植物生长的主要限制。重要的是，频率 在不久的将来，由于气候变化，干旱的严重程度可能会增加。在干燥的土壤植物细胞中 经历渗透压，引发数千个基因的差异表达， 被称为渗透胁迫反应的基因表达。受到压力的植物组织积累这种激素 脱落酸（阿坝）和阿坝信号进一步协调干旱胁迫转录反应。尽管 这些转录变化的大规模，我们对它们伴随的调节知之甚少， 染色质结构也不清楚阿坝激素信号是如何整合到更大的渗透胁迫 反应此外，我们的知识，转录调节介导的渗透胁迫反应， 还远远没有完成。使用参考植物拟南芥，一个强大的遗传模型系统， 拟议的研究将揭示调节程序介导的反应，渗透胁迫在植物根。 本研究的具体目的是：（1）检测渗透胁迫是否驱动染色质结构的变化 使用细胞类型特异性基因组学为随后的应激激素诱导的基因表达准备基因组。 (2)为了进行一个集中的RNAi筛选，以确定新的转录调节因子在渗透调节中发挥作用， 应激反应(3)为了直接可视化渗透胁迫对核结构和动力学的影响， 共聚焦显微镜在活的植物根部。

Project Summary Organisms evolved to survive and reproduce in an environment that changes along many dimensions. As a consequence, genomes respond to environmental stress through major alterations in gene expression. In eukaryotes, environmental and developmental signals interact with the genome through chromatin, thus understanding the role of chromatin structure in the activation of stress dependent gene expression programs is crucial. Therefore, we need new studies dissecting the mechanisms controlling stress responses that are well grounded in organismal physiology. Plants provide a unique opportunity to address this issue. To support a sessile lifestyle, plants evolved sophisticated mechanisms to adjust their growth and physiology to confront environmental challenges such as drought, a major limitation on plant growth. Importantly, both the frequency and severity of droughts will likely increase in the near future due to climate change. In dry soil plant cells experience osmotic stress which triggers the differential expression of thousands of genes, a reprogramming of gene expression known as the osmotic stress response. Stressed plant tissues accumulate the hormone abscisic acid (ABA), and ABA signaling further coordinates drought stress transcriptional responses. Despite the massive scale of these transcriptional changes we know little about their accompanying regulation by chromatin structure nor is it clear how ABA hormone signaling is integrated into the larger osmotic stress response. Additionally, our knowledge of the transcriptional regulators mediating the osmotic stress response is far from complete. Using the reference plant Arabidopsis thaliana, a powerful genetic model system, the proposed research will uncover the regulatory program mediating the response to osmotic stress in plant roots. The specific aims of the proposal are: (1) To test if osmotic stress driven changes in chromatin structure prime the genome for subsequent stress hormone induced gene expression using cell type specific genomics. (2) To carry out a focused RNAi screen to identify novel transcriptional regulators functioning in the osmotic stress response. (3) To directly visualize the impact of osmotic stress on nuclear structure and dynamics using confocal microscopy on live plant roots.