Graduation Semester and Year
Spring 2025
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Biology
Department
Biology
First Advisor
Alison Ravenscraft
Second Advisor
Paul Chippendale
Third Advisor
Jeffery Demuth
Fourth Advisor
Melissa Walsh
Fifth Advisor
Cara Boutte
Abstract
Symbiotic associations with microbes are widespread across life and provide hosts with essential and beneficial functions. A growing concern in pest management is symbiont-mediated detoxification (SMD), a form of metabolic resistance to insecticides. The best-known example of SMD involves the bean bug Riptortus pedestris, where an environmentally acquired but obligate Caballeronia symbiont confers resistance to the organophosphorus insecticide fenitrothion. Motivated by this model, I began my work in another known bug-Caballeronia symbiosis: Leptoglossus phyllopus, native to the United States. I then expanded the study to include two additional U.S.-native hosts, Leptoglossus zonatus and Anasa tristis. Representative gut isolates from all three hosts were screened for their ability to degrade three common insecticides—imidacloprid, fenitrothion, and malathion—in vitro. I also reintroduced degrader strains into hosts to test whether microbial degradation conferred resistance. This work was further extended to the Colorado potato beetle (Leptinotarsa decemlineata), a globally significant pest known for its rapid development of insecticide resistance. In this system, I examined microbial metabolic activity in greater detail, focusing on enantiomer-specific degradation of insecticides over time. Finally, I sequenced and annotated the genomes of identified degrader strains and searched for candidate genes potentially involved in insecticide breakdown. In summary, this dissertation establishes a foundation for understanding how microbial communities influence insecticide dynamics in pest insects. It offers insight into the potential for metabolic resistance within the studied host and lays the groundwork for future studies exploring the role of microbial metabolism in host adaptation to insecticides.
Keywords
Insecticides, Pesticides, Symbiont-mediated detoxification, symbiosis, conferred resistance, insecticide resistance
Disciplines
Environmental Microbiology and Microbial Ecology
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Blanton, Alison G., "Microbial Mavericks: Turning hazards into snacks" (2025). Biology Dissertations. 227.
https://mavmatrix.uta.edu/biology_dissertations/227