Elucidating how drought stress reprograms genome activity

项目摘要 生物体的进化是为了在一个沿许多维度变化的环境中生存和繁殖。作为一名 因此，基因组通过基因表达的重大变化来响应环境压力。在……里面 真核生物、环境和发育信号通过染色质与基因组相互作用，因此 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 在生物生理学方面有很好的基础。植物为解决这一问题提供了一个独特的机会。支持 作为一种固着的生活方式，植物进化出复杂的机制来调整它们的生长和生理来应对 干旱等环境挑战是植物生长的主要限制因素。重要的是，这两种频率 在不久的将来，由于气候变化，干旱的严重程度可能会增加。在干燥土壤中的植物细胞 体验渗透压力，它触发了数千个基因的差异表达，重新编程 基因表达被称为渗透应激反应。受胁迫的植物组织会积累激素 脱落酸(ABA)和ABA信号进一步协调干旱胁迫的转录反应。尽管 这些转录变化的巨大规模，我们对其伴随的调控知之甚少 染色质结构也不清楚ABA激素信号如何整合到更大的渗透胁迫中 回应。此外，我们对调节渗透胁迫反应的转录调控因子的了解 还远远没有完成。利用参考植物拟南芥，一个强大的遗传模型系统， 拟议的研究将揭示调节植物根部对渗透胁迫的反应的调节程序。 该提案的具体目的是：(1)测试渗透胁迫是否会导致染色质结构的变化 使用细胞类型特定基因组学为后续应激激素诱导的基因表达准备基因组。 (2)进行聚焦RNAi筛选以确定在渗透压中起作用的新的转录调控因子 压力反应。(3)直接显示渗透胁迫对细胞核结构和动力学的影响。 活植物根部的共聚焦显微镜。

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.