Abstract:

The adoption of genetically modified （GM） maize has expanded rapidly in China， and it has become the crop with the highest number of safety certificates issued for genetically modified organisms （GMOs）. Therefore， it is essential to establish a specific， sensitive， and operable detection method for GM maize lines. This study designed specific primer-probe sets based on the flanking sequences of the insect-resistant and herbicide-tolerant maize event BBL2-2， establishing a real-time quantitative PCR detection method for this event. The method exhibited high specificity. Its limit of detection （LOD） reached 0.05% （equivalent to 20 copies）， and the limit of quantification （LOQ） reached 0.1% （equivalent to 40 copies）. The standard curve showed excellent linearity， and both the trueness and precision of the method were ≤25%， complying with relevant standard requirements. Inter-laboratory validation results were consistent with internal test results， demonstrating good repeatability and reproducibility. The established uncertainty assessment method was highly operable， ensuring the reliability of quantitative results and providing a basis for labeling threshold management. The developed real-time quantitative PCR detection method for insect-resistant and herbicide-tolerant maize BBL2-2 offers technical support for detection and regulatory oversight， facilitating the commercial deployment of this GM maize event.

Key words: BBL2-2 maize, event-specific PCR, quantitative detection, inter-laboratory validation, uncertainty