EAGER: A Nanobiotechnology Approach to Study the Role of Chloroplasts as Transceivers in Plant ROS Communication

全球大多数农村土地都受到环境压力的影响，包括干旱和极端温度，这些因素严重抑制了植物生长，导致世界各地农作物产量大幅下降。提高我们对植物如何响应和耐受逆境的认识的一个主要限制是理解短暂的和高活性的植物信号分子在细胞内和细胞之间的运动和分布。该项目旨在研究植物细胞如何通过关键信号和化学反应氧分子(ROS)传递各种类型的环境胁迫。目前监测和操纵ROS的方法是基于生物技术工具，仅限于少数几个植物模型系统，缺乏时间分辨率来感知特定亚细胞室中ROS的快速或长期变化。这项研究将利用新兴的纳米生物技术方法来发现由叶绿体等特殊细胞结构介导的植物ROS通讯的新机制。合成的和多功能的基于纳米颗粒的工具有可能很容易从植物模型系统移植到不同的植物物种。该项目将在会议上向植物生物学和工程学多个学科的科学家传播成果，并在当地的公共科学推广活动中传播这些成果。来自不同系和代表性不足群体的新一代本科生和研究生将在实验室接受有关纳米材料的植物生物学研究和工程的培训，并通过纳米生物技术课程在课堂上接受培训。ROS是传递和调节微调植物逆境反应的关键信号分子。植物质外体和叶绿体之间的ROS通讯机制是调控非生物胁迫基因簇表达的关键。已有研究表明，非生物胁迫诱导的ROS质外体波被传递到叶绿体，在叶绿体中引发ROS生成的二次增加。目前尚不清楚叶绿体是否同时作为接收和传输质外体中产生的ROS波的收发者。这项拟议的项目将应用新型的ROS监测和操纵纳米颗粒，以获得对叶绿体在非生物胁迫期间作为ROS振荡波的接收者、放大器、生成器和调制器的假想角色的机械理解。它将测试和模拟这样的想法，即叶表皮细胞中亚细胞ROS波的幅度、持续时间和相位与高光、热和臭氧应激反应独特相关。单壁碳纳米管将被用作体内ROS传感器。这些无限寿命的纳米传感器在近红外线发出荧光，那里的活组织相对透明。它们不会光漂白，具有毫秒时间分辨率和单分子检测的潜力。可以作为催化ROS清除剂的氧化铈纳米颗粒将被定位于质外体和叶绿体，以在这些亚细胞隔间中进行特定的ROS操作。这项研究将证明独特的纳米生物技术方法的概念，以前所未有的时空分辨率在体内研究植物信号传递，并有助于我们理解亚细胞ROS信号如何编码调节植物非生物胁迫反应的源特定信号。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Most global rural land is affected by environmental stresses include drought and extremes in temperature that strongly inhibit plant growth and lead to significant crop yield loss worldwide. A major limitation to advancing our knowledge of how plants respond to and tolerate stress is understanding the movement and distribution of short-lived and highly reactive plant signaling molecules both within and between cells. The project aims to study how plant cells communicate types of environmental stresses through key signaling and chemically reactive molecules of oxygen (ROS). Current approaches to monitor and manipulate ROS are based on biotechnology tools limited to a few plant model systems lacking the temporal resolution to sense rapid or long-term changes in ROS in specific subcellular compartments. The study will utilize emerging nanobiotechnology approaches for discovering novel mechanisms of plant ROS communication mediated by specialized cellular structures such as chloroplasts. Synthetic and versatile nanoparticle-based tools have the potential to be easily translated from plant model systems to diverse plant species. The project will disseminate the results at meetings to scientists across multiple disciplines of plant biology and engineering and at local public science outreach events. A new generation of undergraduate and graduate students from diverse departments and underrepresented groups will be trained in the laboratory on plant biology research and engineering with nanomaterials and in the classroom through a nanobiotechnology course. ROS are key signaling molecules communicating and regulating fine-tuned plant stress responses. The mechanisms involved in plant ROS communication between the plant apoplast and chloroplasts are crucial to control the expression of abiotic stress gene clusters. It has been proposed that abiotic stresses induce ROS apoplastic waves that are transmitted to chloroplasts where they trigger a secondary increase in ROS generation. It is unclear if chloroplasts act as transceivers both receiving and transmitting ROS waves generated in the apoplast. The proposed project will apply novel ROS monitoring and manipulating nanoparticles to gain a mechanistic understanding of the hypothesized role of chloroplasts as receivers, amplifiers, generators, and modulators of ROS oscillatory waves during abiotic stress. It will test and model the idea that the amplitude, duration, and phase of subcellular ROS waves in leaf epidermal cells are uniquely associated with high light, heat, and ozone stress responses. Single walled carbon nanotubes will be used as in vivo ROS sensors. These infinite lifetime nanosensors fluoresce in the near infrared where living tissues are relatively transparent. They do not photobleach and have the potential for millisecond temporal resolution and single molecule detection. Cerium oxide nanoparticles that can act as catalytic ROS scavengers will be targeted to the apoplast and chloroplasts for specific ROS manipulation in these subcellular compartments. The study will demonstrate proof of concept of unique nanobiotechnology approaches to study plant signaling communication in vivo with unprecedented spatiotemporal resolution and contribute to our understanding of how subcellular ROS signals encode source specific signals regulating plant abiotic stress responses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.