Evaluation of GE crop transgene adsorption to microplastics and downstream fate in the environment

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Genetically engineered crops remain controversial because of the unknown impacts these crops and their engineered genes have on human and ecological health. While genetically engineered crop genes can give helpful traits like pesticide resistance to crops, some can also be harmful if they are released in the environment. Antibiotic resistance genes (‘ARGs’) and silencing RNA genes are two examples of genes that are potentially harmful. ARGs can increase the number of antibiotic resistant bacteria in the environment, which is a threat to public health. Silencing RNA genes can affect the genetic material of other organisms and the behavior of these genes in the environment is not well understood. Persistent pollutants like microplastics have been shown to make these genes more stable in the environment, making it more likely that they can be transported widely and negatively affect beneficial organisms. The goal of this research is to assess the transport, persistence, and uptake of ARGs and silencing RNA genes that are attached to microplastics in the environment. Understanding how genetically engineered crop genes behave in the environment is important for many fields including agriculture, medicine, and water treatment. The results have strong potential to advance knowledge and benefit society through the development of risk-based management policies to protect health by minimizing the spread of harmful genes. The use of genetically engineered (GE) crops has remained controversial due to uncertainty regarding the ultimate fate and potential impacts the engineered genes can have on the surrounding environment. Common transgenes contained in modern GE crops include ARGs and silencing RNAs that have recently been detected in wastewater treatment plants and other environments. These findings are concerning because transgene contributions to global antibiotic resistance and their potential impacts to gene expression in environmental microbes are highly uncertain. Transgenes have also recently been shown to adsorb to the surfaces of micro- and nano-scale plastics (‘MNPs’) that are frequently found in wastewater treatment plants and soils, suggesting their transport potential and resistance to degradation in the environment may be greater than currently estimated. The goal of this research is to understand how MNPs impact the transport of GEs in the environment. This goal will be achieved using a combined modeling and experimental approach to: i) Quantify transgene adsorption kinetics to MNPs, soils, and wastewater biosolids; ii) Assess the effects of key environmental factors on the persistence and uptake of GE transgenes; and iii) Evaluate transgene transport and transformation of model soil bacteria in agricultural soils. Successful completion of this research directly addresses important research gaps concerning transgene adsorption to MNPs, their behavior in the environment, and translation of experimental data to modeling frameworks that can be utilized by diverse stakeholder groups. Benefits to society result from interdisciplinary research training for graduate and undergraduate students to improve the Nation’s STEM workforce. Additional benefits result from enhanced scientific literacy through learning modules for undergraduate classes and development of outreach materials focused on microplastics in the environment for K-12 schools in the Palouse region of Washington State.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.