Detection of transgenic crops using improved loop-mediated isothermal amplification method.

Objective To establish a simple visual loop-mediated isothermal amplification(LAMP) detection method for genetically modified(GM) crops.Methods Under an isothermal condition,Bst DNA polymerase amplified the target sequences utilizing a pair of inner primers that contained sequences of sense and antisense strands of target DNA and a pair of displacement primers.The reaction mixture and a high concentration of fluorescent dye SYBR GREENⅠ were placed together in a specially designed reaction tube and the reaction results could be visually detected in the closed tube.Results In this experiment,the exogenous elements nonpaline synthase terminator(T-NOS) and tobacco mosaic virus 35S promoter(P-CaMV35S),which are common in GM crops,were detected by LAMP method.Rice event BT63,maize events BT11,MON863 and soybean event GTS40-3-2 gave T-NOS positive results,rice event BT63,maize event BT11,MON810,MON863 and soybean event GTS40-3-2 showed P-CaMV35S positive results.The T-NOS LAMP and P-CaMV35S LAMP results of non-GM rice,maize and soybean were negative.These results indicate that the T-NOS and P-CaMV35S LAMP detection methods established in this paper were highly specific.In addition,through the detection of GM soybean event GTS40-3-2 simulation samples,it was shown that the sensitivity ofT-NOS LAMP was 0.5%,and the sensitivity of P-CaMV35S LAMP was 0.1%.The detection sensitivity was high.Conclusion The improved LAMP method has high sensitivity and good specificity,which can be used for rapid screening of GM crops.