Date of Award
Doctor of Philosophy
Plant, Soil and Environmental Sciences
Charles N. Stewart
Scott Lenaghan, Feng Chen, Tessa Burch-Smith
As humans pursue space travel and nuclear energy, the risk of harm from ionizing radiation increases. On Earth or in space, plants are essential to our personal and environmental health. Plants serve as sentinels, bioremediators and food sources in areas of high ionizing radiation, therefore it is essential to understand how ionizing radiation affects plant biology. This work aimed to understand plant responses to ionizing radiation in the potato chassis and apply that knowledge to generate novel phenotypes for nuclear energy and space applications. The first gamma radiation phytosensor was developed for monitoring at standoff distances greater than three meters. The expression of Ramazzottius varieornatus (tardigrade) ‘Damage suppressor’ protein was found to be ineffective at increasing plant radiotolerance. Lastly, ionizing radiation response was characterized at low doses, revealing a threshold of response in plants between 2 and 4 Gy. This information can be used to create more sensitive radiation phytosensors and additional radioprotection strategies. All of the work here relied on tissue-specific expression patterns, resulting in a final research chapter on the application of artificial intelligence to understanding cell type differences, so that improved engineering strategies can be generated. This work developed the first field-deployable radiation phytosensor and laid the groundwork for many future phytosensors and radiotolerant plant cultivars. Through this work, humanity can pursue a safer relationship with ionizing radiation.
Sears, Robert Graham, "Characterization of radiotolerance in potato and development of a gamma radiation phytosensor.. " PhD diss., University of Tennessee, 2023.