Real-time PCR for traceability and quantification of genetically modified seeds in lots of non-transgenic soybean

The constant presence of genetically modified (GM) soybean in conventional seed lots has become a growing problem for international seed trade. In this context, seed companies have prompted the development of routine tests for accurate genetically modified soybean seeds detection. In this study, a quantitative PCR-based method was standardized in order to detect and quantify mixtures of seeds (i.e. certified seed) or GM grains (i.e. seeds came from field) into samples of non-GM soybean, in a way that soybean lots can be assessed within the standards established by legislation. The method involved the use of p35S-f2/petu-r1 primers targeting CP-4 enolpyruvylshikimate-3-phosphate synthase (cp4-epsps) gene (i.e. that confers herbicide tolerance in Roundup Ready™ (RR)) for real-time PCR detection and quantification through mericon Quant GMO Detection Assay. The results revealed the method efficiency to detect and quantify the presence of even one soybean seed in batch used for routine evaluation of GM seeds. In addition, it was possible to detect of up to 0.1% of transgenic DNA relative to the soybean grains content. Thus, the sensitive GMO quantitative approach described in this study will provide support in supervising activities, and facilitate the process and control of GM soybean.