Study On Detection Of Genetically Modified Ingredients In Seed Samples From Heilongjiang Field Soybean And Soybean Food In Beijing

China is the original producing area of soybean and has rich cultivars and wild genetic resources. In the case of transgenic soybeans massively imported, the security of the indigenous non-transgenic soybeans in China could be affected. Therefore, the soybean samples from Heilongjiang fields and tofu in Beijing market were collected to detect the genetically modified ingredients.Field soybeans were collected by five-spot sampling from Harbin, Heihe, Jiamusi, Shuangyashan and Jixi of Heilongjiang province and 210 samples were gained. Two DNA extraction methods and extraction effect from seed and leaf of soybean were analyzed. Results showed that GMO DNA extraction method was better than CTAB method, but both DNA template were suitable for PCR amplification. DNA concentration extracted from soybean leaf was higher than from seeds. However, the two extracted DNA were sufficient for PCR amplification.Total 210 soybean samples were analyzed by Qualitative PCR method to detect the presence of RR (Roundup Ready) soybean ingredient. Nested PCR, enzyme digestion and sequencing of amplified pruduct were used to confirm the positive results. Results showed that CaMV35s promoter was not detected from all samples. In Nos terminator analysis, only one sample (No.Oxl) showed a similar amplified fragment and it could be digested into 118bp and 62bp as positive control. CP4-EPSPS gene was amplified from 13 samples, but all of them were proved to be false positives in restriction endonuclease digestion analysis of PCR products. Further analysis by nested PCR indicated that there were no RR soybean ingredients in this sample. Besides, the amplified fragments of 0x1 by CP4-EPSPS primers were sequenced and the results showed it has 81% identity with CP4-EPSPS gene.50 samples of different types and product dates were collected from egg-tofu, vegetable-tofu and so on. Lectin gene, 35s promoter and CP4-EPSPS gene were detected by Qualitative PCR method. Results showed the expected 118bp Lectin band were observed from 50 samples and 35s promoter, CP4-EPSPS gene were not amplified from all samples. Furthermore, real-time fluorescent PCR technology was applied to detect transgenic ingredients from tofu. The detection result was accordant to that of the above common qualitative PCR.