Establishment of a quadruplex real-time PCR for screening of genetically modified tomatoes

Abstract

With the increase in number of the genetically modified (GM) crops authorized worldwide and specific labeling legislation established by many countries, a reliable and efficient method for routine screening of raw material or processed food products needs to be developed. In this paper, a quadruplex quantitative real-time PCR (qPCR) system is described which allows simultaneous detection of one tomato endogenous gene and three most frequently used transgenic elements in GM products: cauliflower mosaic virus 35S promoter, Agrobacterium tumefaciens nopaline synthase terminator, and neomycin phosphotransferase II gene. The specificities of the assays are optimized and validated. In the quadruplex qPCR system, the detection ranges for all of the four genes were determined to be 8–80,000 copies per reaction. Finally, the established detection system was applied in amplification of exogenous and endogenous genes from 33 raw materials and 35 processed products samples. The results indicate that quadruplex qPCR method is feasible for screening of GM tomato products, even for some processed food. As this detection system could be easily applied to the detection of transgenic elements in other plant species, we expect it will meet the challenges of routine GM crop detection resulting from a rapid increase in the number of GM crops in the future.