Droplet digital PCR versus multiplex real-time PCR method for the detection and quantification of DNA from the four transgenic soy traits MON87769, MON87708, MON87705 and FG72, and lectin

New genetically modified (gm) soy crops are going to be released for human consumption. Therefore, analytical skills have to be developed towards an efficient detection and determination of GMO content in feed and food. Existing approaches to screen gm plants do not detect new gm soy traits in many cases. Therefore, a multiplex quantitative real-time PCR system was developed and characterized for the four new transgenic soy traits MON87769, MON87708, MON87705 and FG72 to avoid time- and cost-consuming application of single event detection. It showed amplification efficiency, correlation and limit of quantification similar to the single PCR systems applied. The droplet digital PCR showed increased specificity. In parallel, we developed four duplex droplet digital PCR systems and compared the results from both methods. This showed that both approaches are fit for routine diagnostics. Real-time PCR may be more suited for screening as it is very cost-efficient. Digital PCR may be more suitable for quantitative analysis as it exhibited a measurement uncertainty of only 17 % or below for a single reaction.