Date of Award
Doctor of Philosophy
Plant Pathology and Microbiology
Steven A. Whitham
Utilizing natural and engineered viruses is an accepted approach to studying plant-virus interactions as it relates to symptomology. The majority of the research topics were generated by deciphering where short-comings in the literature existed. Specifically, how Turnip mosaic virus (TuMV) helper component protease (HC-Pro) small RNA (sRNA) binding affinity affects expression of genes correlated with disease phenotypes and studying debilitated viruses in a variety of RNA silencing deficient Arabidopsis thaliana plants. Taken as a whole, the research presented addressed the susceptibility of A. thaliana to TuMV.
The first study was conducted to monitor genes implicated in symptomology in various RNA silencing pathway mutant backgrounds. I hypothesized that an in vitro approach, in conjunction with an in silico study would reveal the mechanism TuMV utilizes to regulate sRNA expression, post-infection. The second study focused on severe, moderate, and weak TuMV strains, versus A. thaliana response to pathogen challenge. I hypothesized that TuMV HC-Pro FRNK box mutants that differed in their ability to infect plants affected the function of host sRNA in graduated steps. I also postulated that these mutants might allow me to uncouple developmental abnormalities associated with disease progression and accumulation of the virus itself. In the final study, I combined my passion for plant pathology and molecular techniques to explore a topic unrelated to potyviruses.
Conclusions based on analyzing the transcripts and sRNAs of genes correlated with TuMV disease symptomology, quantifying their expression in wild-type and RNA silencing defective A. thaliana plants, and characterizing various TuMV viruses lacking RNA silencing suppressor activity will be discussed. Future directions will also be introduced.
Brian Anthony Campbell
Campbell, Brian Anthony, "The Turnip mosaic virus and its effects on Arabidopsis thaliana gene expression" (2013). Graduate Theses and Dissertations. 13049.