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.
