A universal quantification of transgenic soybean eventDAS-68416-4 using duplex digitalPCR

BACKGROUND As labeling thresholds and low level presence thresholds of genetically modified (GM) components are implemented in more and more countries and regions, the demands for accurate quantification are increasing rapidly. At the same time, digital polymerase chain reaction (PCR) showed considerable benefits compared with former real-time fluorescence PCR in GM component quantification. RESULTS A universal quantification method using duplex digital PCR was established for detection of transgenic soybean event DAS-68416-4. The absolute limits of quantification (LOQs) of DAS-68416-4 event-specific gene and lectin reference gene were 0.61 copies mu L(-1)and 4.6 copies mu L(-1)respectively in droplet digital PCR, while 0.522 copies mu L(-1)and 5.192 copies mu L(-1)in chip digital PCR. The relative LOQs of DAS-68416-4 percentage content was 0.1% in both two digital PCR systems. CONCLUSION Gene copy ratio is the universal means of expression internationally used in transgenic component contents. Digital polymerase chain reaction (PCR) executes absolute quantification on specific genes, thus is considered to be suitable for detection of transgenic component contents. It was proved in this research on transgenic soybean event DAS-68416-4. Results indicated perfect satisfaction for transgenic component quantification needs in various technical performances of duplex digital PCR including repeatability, quantitative linear relationship and relative limits of quantification. (c) 2020 Society of Chemical Industry

Automated summary

With the implementation of labeling thresholds and low level presence thresholds for genetically modified (GM) components in more countries and regions, the demand for accurate quantification is rapidly increasing. Digital polymerase chain reaction (PCR) has shown considerable benefits in GM component quantification compared to traditional real-time fluorescence PCR. A universal quantification method using duplex digital PCR was successfully established for the detection of transgenic soybean event DAS-68416-4, with satisfactory results in various technical performances including repeatability, quantitative linear relationship, and relative limits of quantification.