Comparison and transfer testing of multiplex ligation detection methods for GM plants

Of the ligation protocols tested in this study, the best results were obtained with the PPLMD I and PPLMD II protocols and no consistent differences between these two protocols were observed. Both protocols are based on padlock probe ligation combined with microarray detection. Twenty PLPs were tested for specificity and the best probes were subjected to further evaluation. Up to 13 targets were detected specifically and simultaneously. During the interlaboratory exchange study similar results were achieved by the two participating institutes (NIB, Slovenia, and RIKILT, the Netherlands).From the comparison of ligation protocols it can be concluded that two protocols perform equally well on the basis of the selected set of PLPs. Using the most ideal parameters the multiplicity of one of the methods was tested and 13 targets were successfully and specifically detected. In the interlaboratory exchange study it was shown that the selected method meets the 0.1% sensitivity criterion. The present study thus shows that specific and sensitive multidetection of GMO targets is now feasible.The adoption of crops that are genetically modified organisms (GMOs) has continuously increased over the last decade with 148 million hectares grown in 2010 worldwide [1]. Because of the increasing number of GM crops, the analysis of an individual food or feed sample for the potential presence of GMOs becomes more complex, time-consuming and expensive. To overcome these problems it is necessary to develop a method which can identify many GMO-derived DNA targets in a single experiment, at a sensitive level, reducing both cost and analysis time. The potential presence of unauthorized GM crops makes the situation even more complicated [2,3].Currently, the most common method to detect and identify GMOs in food and feed products is real-time polymerase chain reaction (PCR). For most targets this method has a limit of detection (LOD) of 0.1% or less. In the scientific literature, different multip