Application of Digital PCR in the Analysis of Transgenic Soybean Plants

Detection and quantification of transgenes are important in analyzing genetically modified organisms (GMOs). Quantitative polymerase chain reaction (qPCR) is commonly utilized for such purposes. However, qPCR has certain limitations in detecting and quantifying transgenes in GMOs, such as the need of certified reference materials, a standard curve, and possible affection by inhibitors. Therefore, alternative and possibly better methods are needed. Recent advances in digital PCR technologies have promised to allow accurate quantification of nucleic acids and therefore provided another useful technique to analyze GMOs. Thermo Fisher ScientificTM has recently commercialized the Applied BiosystemsTM QuantStudioTM 3D digital PCR system that can be used for a wide range of applications involving nucleic acids. It will be beneficial to the scientific community to show the applicability of this digital PCR system in detecting and quantifying transgenes in GMOs. In the present study, the transgenes present in the Roundup Ready Soybean (RR1, event 40-3-2) and Roundup Ready Soybean 2 (RR2, event MON89788) developed by Monsanto Corporation were analyzed by using this digital PCR system. The qPCR analysis results were included for comparison. Using specifically designed TaqMan assays, as low as 1% of the RR1 or RR2 soybean material was reliably detected and quantified on the dPCR platform. Therefore, digital PCR is a sensitive and reliable method to analyze the RR transgenic soybeans, and should be another useful tool for analyzing other transgenic plants.