Date of Defense

4-17-2020

Date of Graduation

4-2020

Department

Chemistry

First Advisor

Kathryn Docherty

Second Advisor

Pamela Hoppe

Abstract

Widespread antibiotic use in agriculture spreads antibiotic resistance (AR) genes throughout the ecosystem and can impact bacterial community composition and function. Restoring agricultural fields back to their native prairies has been shown to remediate other damaging effects of agriculture, and have the potential to remediate AR from the soil as well. In this study, our first aim was to determine if soil bacterial communities return to pre-agricultural conditions over time following restoration to native plant communities. We did this by assessing the soil characteristics, extracellular enzyme activities, bacterial community composition, and functional metagenomics across a chronosequence of seven restored prairies, one old-field, and one current agricultural plot. We used functional metagenomics to analyze the relative abundances of predicted pathways for antibiotic production and antibiotic resistance across the chronosequence. Though our chronosequence is limited in data points, soil bacterial communities appear to return to pre-agricultural conditions as soil characteristics, and community composition and function converge to similar properties as was found in the old field by 30 years since initial restoration. However, more replicates are needed to draw any definitive conclusions. Production of antibiotics frequently used in agriculture, such as streptomycin and tetracycline, decrease with age of restoration, while pathways for production of antibiotics that are traditionally produced by fungi, such as penicillin or cephalosporin, increases with age of restoration. Correspondingly, ß-lactam resistance and caprolactam degradation follow the same trend as penicillin or cephalosporin production. Our results indicate that prairie restoration may be a useful strategy for addressing the consequences of agricultural antibiotic use.

Access Setting

Honors Thesis-Open Access

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Included in

Agriculture Commons

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