Development of Genomic DNA Certified Reference Materials for Genetically Modified Rice Kefeng 6

The application of certified reference materials (CRMs) to genetically modified organism (GMO) detection is essential for guaranteeing the accuracy, comparability, and traceability of quantitative results over time and among laboratories. Clean leaves from GM rice Kefeng 6 were used as raw materials to develop a batch of genomic DNA (gDNA) CRMs. The optimized KF6/PLD duplex digital PCR was used for collaborative characterization of Kefeng 6 gDNA CRMs by eight qualified laboratories; this batch of gDNA CRMs was certified for two property values, namely, copy number ratio and copy number concentration, which were 1.03 ± 0.04 and (1.60 ± 0.11) × 10⁵ copies/μL, respectively. The gDNA CRMs displayed good between-vial homogeneity when the minimum sample intake of 2 μL was taken into account. Stability studies indicated that the gDNA CRMs should be transported below 25 °C, and cold chain transport was recommended. Shelf life was assessed to be at least 12 months, and when using gDNA CRMs, freeze-thaw should not exceed 10 cycles. Compared to the available gDNA CRMs in the market, this batch of gDNA CRMs has accurate property values with combined uncertainties, providing user-friendly calibrators for GM rice Kefeng 6 inspection and monitoring. The development and characterization of Kefeng 6 gDNA CRMs contribute to the establishment of a copy number-based reference system for GMO detection.