Rapid visual detection of phytase gene in genetically modified maize using loop-mediated isothermal amplification method

Transgenic maize plant expressing high phytase activity has been reported and approved by Chinese government in 2009. Here, we report a highly specific loop-mediated isothermal amplification (LAMP) method to detect the phytase gene in the GMO maize. The LAMP reaction takes less than 20 min and the amplification is visible without gel electrophoresis. The detection sensitivity of the LAMP method is about 30 copies of phytase genomic DNA, which is 33.3 times greater than the conventional PCR method with gel electrophoresis. The quantitative detection results showed that the LAMP method has a good linear correlation between the DNA copy number and the associated Tt values over a large dynamic range of template concentration from 6 × 101 to 6 × 107 copies, with a quantification limit of 60 copies. Therefore, the LAMP method is visual, faster, and more sensitive, and does not need special equipment compared to traditional PCR technique, which is very useful for field tests and fast screening of GMO feeds.