Application of Digital PCR in Analyzing Transgenic Soybeans

Detection of a transgene and quantification of its copy numbers are very important in characterizing transgenic plants. Digital PCR technologies have provided a useful technique to analyze GMOs. With Life Technologies’ Collaborative Research Compacts (CRC) Grant funding, we applied the digital PCR to analyze transgenic soybeans in the present study. Firstly, the transgenes present in the Roundup Ready Soybean (RR1, event 40-3-2) and Roundup Ready Soybean 2 (RR2, event MON89788) were analyzed. By using target-specific TaqMan assays, as low as 1% of the RR1 or RR2 soybean material was reliably detected and quantified on this dPCR platform. Therefore, digital PCR is a sensitive and reliable method to analyze the RR transgenic soybeans, and should be a useful tool in detection and quantitation of other GMOs. Secondly, multiple transgenic soybean lines overexpressing a cell wall modification enzyme were developed in the PI lab. Using Specific TaqMan assays on the QuantStudio 3D Digital PCR system, we have succeeded in detecting and quantifying the transgene in multiple transgenic soybean lines with different copies of the transgene.  Our work suggests that digital PCR can save time and improve detection limit when compared with southern blot and qPCR methods. Furthermore, the digital PCR method allowed identification of chimeric plants at T0 generation and homozygous plants at T1 generation. So it will be beneficial to the scientific community to show the applicability of this digital PCR system in detecting and quantifying transgenes in GMOs.