Real-time loop-mediated isothermal amplification for the CaMV-35S promoter as a screening method for genetically modified organisms

A method has been developed to detect genetically modified organisms (GMOs). The detection method is based on the loop-mediated isothermal amplification (LAMP) reaction. Cauliflower mosaic virus 35S (CaMV-35S) promoter gene, a widespread genetic element, was amplified by a set of LAMP primers. One of the characteristics of the LAMP method is its ability to synthesize an extremely large amount of DNA. Accordingly, a large amount of byproduct, pyrophosphate ion, is produced, yielding a white precipitate of magnesium pyrophosphate in the LAMP reaction mixture. The measurement of the turbidity of the reaction mixture allows easy detection of amplification of CaMV-35S promoter gene without the need for gel electrophoresis. With this new technique we analyzed Roundup Ready soybean, and found GMO content ranging from 0.5% to 5%.