Ultrasensitive Hexaplex Droplet Digital Polymerase Chain Reaction Assay for Rapid Screening and Quantification of Genetically Modified Content

The screening of genetically modified (GM) contents targeting commonly used regulatory elements is the prior step in routine lab analysis. However, the screening analysis of multiple elements with high efficiency, high accuracy, and low costs is still challenging. In this study, we developed a hexaplex droplet digital polymerase chain reaction (ddPCR) assay targeting six commonly used regulatory elements (pCaMV35S, pFMV35S, pNOS, pTA29, tOCS, and tNOS) for rapid and ultrasensitive screening analysis of GM content in food/feed samples. Six targets were identified and quantified in one reaction, and the limits of detection and quantification were 10 copies and 20 copies per reaction, respectively. Further, the 6-plex ddPCR assay showed high accuracy and precision in the quantification of simulated and practical samples when compared with individual simplex ddPCR assays. Our results indicate that the established 6-plex ddPCR assay is suitable for GM content screening analysis in routine genetically modified organism (GMO) analysis owing to its high sensitivity, accuracy, and precision and low cost.