A novel trait-specific real-time PCR method enables quantification of genetically modified (GM) maize content in ground grain samples containing stacked GM maize

Abstract

The GMO contents of two genes were quantified using a plasmid calibrant and summed for quantification of total GMO content. The trait-specific method revealed lower biases for examination of test samples containing stacked GM maize compared with the event-specific method. Our results clearly show that the trait-specific method is not only simple and cost-effective, but also useful in quantifying the GMO content in ground grain samples containing stacked GM maize, which are expected to be major events in the near future. The developed method would be the only feasible way to conduct the quantification of GMO content in the ground maize samples containing stacked GM maize for the verification of the labeling regulation.

DNA-based Methods for Detection of Genetically Modified Events in Food and Supply Chain

“…For example, cry1Ac, cry2Ab genes for insect resistance in Bollgard ® II (MON15985) event of cotton, and cp4-epsps for herbicide tolerance in Roundup Ready ® cotton (MON1445) can be used for testing the presence of these events, after the screening tests targeting p35S and Tnos, present in both these events (MON15985 and MON1445). Gene-specific PCR/qPCR assays have been developed for cry1A.105, cry1A3, cry1Ac, cry2Ab2, cry9C, cry1Ab, epsps, pat, vip3A, AmA1 [18][19][20][21][22][23][24][25][26][27] .…”

Development and Interlaboratory Validation of a Simple Screening Method for Genetically Modified Maize Using a ΔΔCq-Based Multiplex Real-Time PCR Assay

“…Genomic DNA was extracted and purified from 1 g of maize flour using the DNeasy Plant Maxi Kit (QIAGEN, Hilden, Germany) as described previously . DNA concentrations were determined by measuring ultraviolet (UV) absorption at 260 nm with a ND-1000 spectrophotometer (NanoDrop Technologies, Wilmington, DE).…”

“…MON810 or MIR162 flour was mixed with non-GM maize flour at 1, 2, 3, 4 and 5% (w/w) on a 1-g scale. Genomic DNA was extracted from the mixed flours or non-GM maize flour as described previously . The extracted DNA samples were diluted to 20 ng/μL with sterile distilled water.…”

Influence of Heat Processing on DNA Degradation and PCR-Based Detection of Wild-Type and Transgenic Maize

“…At present, various PCR-based methods have been developed for maize identification and for the detection of GM varieties [5,[19][20][21][22][23][24][25][26][27][28]. e conventional PCR methods targeted at the invertase gene [23,24], Zea mays 10 KDa zein gene [25], and quantitative real-time PCR assays targeted at zein, and alcohol dehydrogenase I (Adh-1) genes [26] and starch synthase IIb gene [27] were developed and successfully used for specific identification of corn.…”

“…e conventional PCR methods targeted at the invertase gene [23,24], Zea mays 10 KDa zein gene [25], and quantitative real-time PCR assays targeted at zein, and alcohol dehydrogenase I (Adh-1) genes [26] and starch synthase IIb gene [27] were developed and successfully used for specific identification of corn. Different types of quantitative real-time PCR-based assays were applied for screening, identification, and quantification of transgenic events [26][27][28][29]. A number of studies have investigated the influence of food processing on plant DNA degradation and GMO detection [9][10][11][12][13][14][15][16][17][18][19][20].…”