Endpoint visual detection of three genetically modified rice events by loop-mediated isothermal amplification

Area of Science:

• Agricultural Biotechnology
• Molecular Biology
• Food Safety

Background:

• Genetically modified (GM) rice varieties, including KMD1, TT51-1, and KF6, are prevalent in China.
• Existing methods like polymerase chain reaction (PCR) for GM detection are complex and time-consuming.
• A need exists for rapid, sensitive molecular assays for GM rice risk assessment.

Purpose of the Study:

• To develop a visual and rapid loop-mediated isothermal amplification (LAMP) method for detecting specific transgenic Bt rice events.
• To assess the specificity and sensitivity of the developed LAMP assay compared to conventional PCR.
• To establish a simple, field-deployable test for GM rice identification.

Main Methods:

• Developed event-specific primer sets for three GM rice lines (KMD1, TT51-1, KF6).
• Employed loop-mediated isothermal amplification (LAMP) at a constant 63 °C for DNA amplification.
• Utilized SYBR green or hydroxy naphthol blue (HNB) for visual detection of amplified products.
• Tested specificity using various plant types and determined sensitivity limits.

Main Results:

• The LAMP assay successfully amplified target DNA from GM rice within 60 minutes.
• Visual detection was achieved using SYBR green or HNB indicators.
• The assay demonstrated high specificity, with negative results for non-target plants.
• Sensitivity was significantly higher than conventional PCR, with detection limits as low as 0.005% GM DNA.
• The LAMP method proved 10- to 100-fold more sensitive than PCR.

Conclusions:

• The developed visual and rapid LAMP method is a highly sensitive and specific tool for detecting GM rice.
• This assay is suitable for simple, field-based risk assessment of genetically modified crops.
• LAMP offers a significant advancement over conventional PCR for routine GM detection.