A new construct specific real-time PCR method for screening GMO ingredients with gat-tpinII cassette in foods, feeds and seeds

With the number of genetically modified (GM) events authorized or pending for authorization yearly growing steadily, screening approaches need to be updated to enable full coverage and better discrimination of all these events. A construct-specific quantitative polymerase chain reaction (qPCR) assay for screening genetically modified organisms (GMO) with gat-tpinII cassette was developed in response to that need. The specificity of the built method was evaluated by testing commercial GM events and the sensitivity and repeatability were also assessed and validated. The limit of detection (LOD) could be as low as 5 copies, and the limit of quantification (LOQ) was 40 transgenic haploid genome copies. Three certified reference materials (CRMs) at known concentrations were analyzed as unknown samples to verify the developed real-time PCR system. And no substantial bias was shown with high accuracy. Thirty-five food products containing soybean, maize or canola were collected from the markets as practical samples and further validated the screening applicability of the built method. The results suggested that the method could be reliably used for identification of GM events with gat-tpinII construct in plant-derived samples.