ORNL Biosensor Tracks RNA Activity in Plants, Enhancing Crop Development

Oak Ridge National Laboratory (ORNL) scientists have developed a biosensor technology that enables the visualization and real-time tracking of ribonucleic acid (RNA) activity within living plant cells. This innovative method combines a molecular splicing technique with a fluorescent marker protein. This new approach allows researchers to detect and monitor changes in RNA and gene expression in real-time. It provides a valuable tool for enhancing bioenergy and food crops and identifying unwanted plant modifications, pathogens, and pests. RNA, a signaling molecule, translates DNA code into functional components like proteins, which are crucial for plant growth and stress response. The ORNL-developed biosensor continuously monitors RNA levels in live plants, replacing the traditional method of tissue collection, processing, and analysis. According to Xiaohan Yang, the project lead at ORNL, the biosensor offers "real-time insights into how cells reprogram themselves at a molecular level under changing environmental conditions such as drought or disease." The biosensor works by splitting a ribozyme—an RNA molecule that catalyzes RNA splicing—into two inactive parts. These parts are then attached to guide RNA sequences that bind to a specific RNA target inside the plant cell. When the guide RNA finds its target, the ribozyme pieces rejoin, activating a reporter protein that produces visible fluorescence. This fluorescence indicates the RNA's location and abundance. The biosensor's functionality was demonstrated by detecting a virus infecting a tobacco plant and by revealing gene activity in *Arabidopsis*. The system can detect gene activity from individual cells to the tissue level across the entire plant, including leaves, roots, flowers, and stems. Paul Abraham, co-author and manager of the DOE Secure Ecosystem Engineering and Design Science Focus Area (SEED SFA), noted the biosensor's utility in observing when and where a plant begins to reprogram itself in response to conditions like drought. Jerry Tuskan, co-author and director of the DOE Center for Bioenergy Innovation, added that the biosensor's versatility extends from improved functional genomics to practical applications such as screening plant performance for early detection of pathogens or other stress responses. ORNL's work aims to foster innovations for domestic, affordable bio-based fuels, chemicals, and materials, building on its history of biological and genetics research. Paul Langan, associate laboratory director, highlighted that the discovery of messenger RNA originated with ORNL biologists and chemists in the 1950s. The project received support from the SEED SFA and the Center for Bioenergy Innovation, with funding from the DOE Office of Science Biological and Environmental Research program.