A rapid DNA lateral flow test for the detection of transgenic maize by isothermal amplification of the 35S promoter

The present study describes an isothermal DNA amplification method combined with a rapid visual signal read-out for the detection of the 35S promoter, a regulatory element commonly found in GM plants and often used for screening of genetically modified crops. The amplification of the target sequence is accomplished by helicase-dependent amplification (HDA), which can be entirely performed on a simple heating block, within 60 min reaction time and without costly instrumentation. For visualisation of the amplified products, a nucleic acid lateral flow immunostrip is applied, which enables the detection of the formed products within 5-10 min and simply by naked eye. The specificity and sensitivity of the developed assay were tested and determined by analysing certified reference materials of MON810, Bt11 and NK603. The obtained limit of detection is 0.5% GM content, which fulfils the European demands for mandatory labelling of any food and feed that contains more than 0.9% GM components. A novel DNA strip test enables the detection of low amounts of the 35S promoter of genetically modified organisms.