A novel quantitative technique in detecting stacked genetically modified plants by fluorescent-immunohistochemistry

Stacked genetically modified organisms (GMOs) are gaining popularity for their ability to enhance production efficiency and improve functional properties. Due to different labeling requirements across many countries, the detection and quantification of stacked GMO content is an important concern. Although existing methods can detect pure stacked GMOs, they are considerably less efficient at identifying material that contains the stacked GMO and its single-trait parent GM lines. Immunohistochemistry possesses superior specificity and sensitivity in detecting the target, especially proteins. As a result, a novel quantitative technique to detect stacked GMO was developed. Two fluorescent antibodies hybridized with two specific proteins, which were expressed by the single-trait parents separately, were employed. By observing whether both of the two fluorescent signals existed in the same cell, the stacked GMO could be easily detected. By calculating the fluorescent signals, quantification could be determined. This method reduces errors and the non-specificity caused by PCR-based methods, and is widely applicable in the quantitative and qualitative detection of stacked GMOs. In sum, it represents a new method for high throughput detection.