Investigating the Role of Genetically Modified Crop Transgenes in Antibiotic Resistance in the Environment

Duke University, Durham NC

Investigators

Abstract

1438612 Gaunsch Investigating the Role of Genetically Modified Crop Transgenes in Antibiotic Resistance in the Environment In 2013, approximately 90 % of the US corn crop was genetically modified. As part of the genetic modification process, selectable marker genes including antibiotic resistance genes are inserted into genetically modified crops. The fate of these genes is important to quantify, especially in the context of wastewater sewage sludge (biosolids). The land application of biosolids makes it critical that the fate of these genetically modified crop transgenes be investigated. The data generated will be useful to industry as well as legislators who control the future of genetically modified crops both domestically and internationally. The overall goal of this project is to determine if genetically modified crops are a significant source of antibiotic resistance genes. We hypothesize that genetically modified crop transgenes are an important contributor to bacterial antibiotic resistance development mainly because of the smaller size of the genetically modified crop plasmids relative to naturally occurring antibiotic resistant plasmids. This hypothesis will be tested in three tasks; 1) Genetically modified corn and soybean transgenes will be quantified in various wastewater treatment facilities. 2) The persistence of antibiotic resistance genes originating from plasmids used in genetically modified corn and soybean crops will be compared to naturally occurring plasmids during a simulated wastewater treatment and biosolids land application event. 3) Antibiotic resistance genes horizontal transfer rates will be compared between small plasmids (representative of genetically modified crop plasmids) and large plasmids (representative of naturally occurring plasmids carrying antibiotic resistance genes). The expected results from this research consist of identifying whether: 1) genetically modified crops are an important contributor of antibiotic resistance genes in the environment and; 2) biosolids land application promotes the proliferation of genetically modified crop associated antibiotic resistance genes. The success of the research work plan will be measured by our ability to quantify genetically modified crop derived antibiotic resistance genes and to determine their role in global antibiotic resistance development. A successful outcome of this project will lead to a better understanding of the long term implications of utilizing antibiotic resistance genes as selectable marker genes in genetically modified crop engineering.