Development of Gene-Specific Real-Time PCR Screening Method for Detection of cp4-epsps Gene in GM Crops

Among the genetically modified (GM) crops that are being approved for commercialization, herbicide resistant crops, especially those harboring cp4-epsps, have a considerable contribution. Gene-specific methods can be used to screen the presence of GMOs. To establish an effective qualitative and quantitative screening method, a set of primers were designed considering the cp4epsps sequence. The specificity, the limit of detection, the efficiency, and the ability to quantify the GMO content were tested in GM cotton, soybean, and canola events. The results demonstrated that the primers can specifically detect cp4-epsps GM crops. The limit of detection was found to be 0.4 ng /μl DNA per PCR reaction with the ability to detect 1-16 copies of the haploid genome of each GM event. The efficiency of this screening method (which was 94-110 % with an R2 higher than 0.96) indicated that these new primers can be applied to the screening of GM samples that contain the cp4-epsps gene. Also, the gene-specific real-time PCR screening method could be successfully developed for qualification of different types of GM cotton, soybean and canola events with the construction of a serial dilution ranging from 10 % to 1 %.