PCR detection of transgenic maize on the basis of P35S

In the past two decades, biotechnology in genetic engineering has led the production of genetically modified organisms (GMOs) all around the world. The statistics of GMO cultivation has lightened the significant importance of GMOs worldwide, and shows that they are widely consumed by public. Maize is one of the most important transgenic crops which has widely cultivated and consumed in many countries. The aim of this study is the detection of genetically modified maize in Iran markets. First, three samples of transgenic maize were prepared from Shiraz’s Custom and their DNA was extracted using Cetyl Tri-methyl Ammonium Bromide (CTAB) method. The control PCR test of native maize was performed on Invertase (IVR) gene which is present in all corn types. For detection of genetically modified maize, the PCR test based on P35S promoter which present in most transformation vectors was optimized using specific primers (P35S1 and P35S2). Then, DNA of 37 maize samples collected from seven major cities of Iran and six maize samples from Jihad Agriculture Organization were extracted. PCR tests for the IVR gene and P35S were performed. Respectively, the 226 bp and the 195 bp amplicons were amplified. PCR products were cloned by T/A cloning in JM107 using pTZ57R plasmid for sequencing and preparing the positive controls. 46 samples collected from the market, Customs and Jihad Agriculture Organization were shown to be 100% positive for the native IVR gene and 56.5% (26 samples) positive for the exogenous P35S. This study showed that a high percentage of transgenic maize is present in Iran’s consumption market. However, no action has been taken toward labeling and the consumer awareness of these food products.