Event-specific detection system of stacked genetically modified maize by using the multiplex-PCR technique

Stacked genetically modified (GM) crops are becoming popular for their enhanced production efficiency and improved functional properties. In this study, we developed an event-specific PCR method for simple qualitative detection of stacked events combining more than 2 transgenic traits. Ten primer sets were designed, including 9 that were event-specific and 1 that was specific for a maize endogenous gene. Five event-specific multiplex-PCR systems were built, based on the main type of stacked GM events approved in Korea. Multiplex PCR was performed with mixtures of template DNA extracted from certified reference materials. PCR amplicons (3 or 4 by type) of expected sizes and mutually similar intensities were detected. The limit of detection was approximately 0.1%(v/v) for stacked GM maize in all event-specific PCRs. This method may be useful for the specific detection and monitoring of stacked GM maize lines and individual parent GM maize lines, by effectively distinguishing genestacked events.