A survey of crop-derived transgenes in activated and digester sludges in wastewater treatment plants in the United States.

TitleA survey of crop-derived transgenes in activated and digester sludges in wastewater treatment plants in the United States.
Publication TypeJournal Article
Year of Publication2018
AuthorsCM Gardner, CA Gwin, and CK Gunsch
JournalWater Science and Technology : a Journal of the International Association on Water Pollution Research
Volume77
Issue7-8
Start Page1810
Pagination1810 - 1818
Date Published04/2018
Abstract

The use of transgenic crops has become increasingly common in the United States over the last several decades. Increasing evidence suggests that DNA may be protected from enzymatic digestion and acid hydrolysis in the digestive tract, suggesting that crop-derived transgenes may enter into wastewater treatment plants (WWTPs) intact. Given the historical use of antibiotic resistance genes as selection markers in transgenic crop development, it is important to consider the fate of these transgenes. Herein we detected and quantified crop-derived transgenes in WWTPs. All viable US WWTP samples were found to contain multiple gene targets (p35, nos, bla and nptII) at significantly higher levels than control samples. Control wastewater samples obtained from France, where transgenic crops are not cultivated, contained significantly fewer copies of the nptII gene than US activated and digester sludges. No significant differences were measured for the bla antibiotic resistance gene (ARG). In addition, a nested PCR (polymerase chain reaction) assay was developed that targeted the bla ARG located in regions flanked by the p35 promoter and nos terminator. Overall this work suggests that transgenic crops may have provided an environmental source of nptII; however, follow-up studies are needed to ascertain the viability of these genes as they exit WWTPs.

DOI10.2166/wst.2018.051
Short TitleWater Science and Technology : a Journal of the International Association on Water Pollution Research