Event-specific quantitative detection of nine genetically modified maizes using one novel standard reference...

Area of Science:

• Agricultural Biotechnology
• Molecular Biology
• Genetics

Background:

• Polymerase Chain Reaction (PCR) is crucial for genetically modified organism (GMO) detection, with real-time PCR being key for quantification.
• Event-specific detection targets unique integration junction sequences for high specificity in GMO analysis.
• Existing challenges include obtaining certified reference materials for accurate GMO quantification.

Purpose of the Study:

• To establish and optimize event-specific TaqMan real-time PCR detection methods for nine genetically modified maize events.
• To develop a novel standard reference molecule for accurate quantification of multiple GM maize events.
• To evaluate the performance of the developed methods in terms of accuracy and precision.

Main Methods:

• Development of event-specific TaqMan real-time PCR assays targeting unique integration junction sequences.
• Optimization of PCR conditions, including the use of TAMRA as a fluorescent quencher.
• Construction of a novel standard reference molecule incorporating nine GM maize event sequences and a maize endogenous gene (zSSIIb).
• Quantitative analysis of mixed maize samples to assess accuracy and precision.

Main Results:

• Established event-specific detection methods for TC1507 and CBH351 maize, and optimized methods for seven additional GM maize events (Bt11, Bt176, GA21, MON810, MON863, NK603, T25).
• Developed a novel reference molecule for accurate quantification across multiple GM maize events.
• Achieved limits of detection and quantitation at approximately 20 copies, with dynamic quantification ranges from 0.05% to 100%.
• Demonstrated high accuracy (bias 0.67-28.00%) and precision (RSD 0.83-26.20%) in analyzing mixed maize samples.

Conclusions:

• The developed event-specific real-time PCR systems are suitable for identifying and quantifying the nine tested GM maize events.
• The novel reference molecule effectively supports accurate and precise quantitative analysis of these GM maize events.
• These advancements contribute to reliable detection and monitoring of genetically modified crops.