The Environmental Fate and Effects of Antibiotic Resistance Genes and Small Interference RNAs From Genetically Modified Crops

Increasing rates of global population growth have amplified food scarcity across the globe and ushered in the development of genetically modified (GM) crops to meet different needs, such as increasing food demands and longer crop shelf life that are otherwise hard to attain. Modern crops that use small interference RNA (siRNA) and antibiotic resistance genes (ARGs) have become increasingly common in the United States. GM crops remain controversial due to the uncertainty regarding possible unintended effects on the environment. ARGs or siRNAs from GM crops may be released during plant decomposition and adsorbed by soil, which can persist across large time scales, remain bioavailable in soil or water, and can lead to possible uptake by soil microbial communities. These genes can potentially contribute to antibiotic resistance as well as disrupt nutrient cycling and soil fertility. Therefore, siRNAs and ARGs which are emerging contaminants are a problem. Further information on the environmental effects of these genetic constructs is required as well as research focused on the genetic transfer to belowground microbes, transport, and fate. By understanding the interaction and dynamics of transgenes and microbes, as well as determining transgene fate and transport in soil, risks can be predicted and effectively remediated, and farming practices can be optimized. Thus, the goal of this research is to assess the fate of GM crop ARG and siRNA transgenes in soil and determine the ecological impacts of their transfer to microbes using laboratory-based experiments. It is hypothesized that transgenes are persistent and motile in soils, and horizontal gene transfer can occur if the conditions are optimal for bacterial uptake. Preliminary research suggests homology between transgenes and soil bacteria genetic sequences. Further research will consist of soil batch reactors to determine the persistence and transport of transgenes in soil and soil columns to evaluate transgene influence on structures and functions of microbial communities.