Field Detection of Genetically Modified Crops: Simple DNA Extraction, Rapid Assay and Automatic Output on Smartphone

Rapid and accurate detection of genetically modified crops (GMC) is significant for crop supervision and genetically modified product labeling. For field detection of GMC, the rapidity and simplicity of the sample pretreatment and detection process are very important. Simplifying the extraction process of DNA in crops and speeding up the detection process are the technical problems that need to be solved. Therefore, this paper provides a field detection method for GMC. First, the selected universal LAMP primers of the chloroplast gene can be used to detect reference genes in nine crops with the most transgenic detection needs. The universal primers of reference genes can not only improve the accuracy of detection, but also omit the design and synthesis of reference gene primers in different crops. Second, a high concentration of DNA can be obtained using simple and fast DNA extraction methods within 5 min. The specific concentration of GuHCl in lysis buffer can accelerate the subsequent nucleic acid amplification reaction. Third, a new probe-LAMP method was established, with high reaction speed and specificity. Using the dual probe-LAMP for transgenic and reference genes in a handheld nucleic acid detector, the detection of GMC can be completed within 25 min. Two different fluorescence signals generated from the LAMP reaction are processed through a special logic gate, and finally three kinds of results of "Positive", "Negative" and "Invalid" are output on a smartphone. This method from sample processing to intelligent result output can achieve accurate, rapid, simple, low-cost, pollution-free field detection of GMC.