Study On Some Factors Affecting The Accuracy Of Rice And Rice Products Detection Of Genetically Modified Ingredients

In this study, some factors are analyzed to establish the best methods which could improve the detection effect of genetically modified (GM) ingredients of rice products, which include the fineness of rice and rice products, the incubating time in the CTAB solution during the DNA extraction process, and the fluorescence PCR reaction system.With GM rice kefeng6and non-GM rice, four gradient of simulation genetically rice and rice products positive samples can be made:1%、0.1%、0.01%、0.001%. Set three kinds of abrasive particle fineness of samples (<50mesh,50～100mesh,>100mesh) and three kinds of CTAB incubating time(1h、4h、>8h)during the DNA extraction of the samples, and there will be a total of nine kinds of pretreatment combination. Extract the DNA of samples under different pretreatment conditions. Endogenous gene GOS and exogenous genes CaMV35S, NOS, Cry1Ab/c and Ub-c were tested by optimized fluorescence PCR. F test is used to analyze the significant differences between the test results—Ct value, according to the multiple comparison, select the best pretreatment sample fineness and CTAB incubating time for DNA extraction and the fluorescent PCR detection.F test results show that:in the9kinds of processing combinations, there are very significant differences from DNA extraction concentration of rice and rice products, and significant or very significant influence were existed among the Ct value of endogenous gene GOS and four exogenous genes of rice.Multiple comparison results show that, for rice and the two kinds of rice products (rice cake slice and rice noodle), the best combination of sample fineness and CTAB incubating time for each gene’s test is grain thickness with>100mesh and CTAB buffer incubating time as>8hours.In this paper, after determining the best combination of sample preparation, the detection experiment was carried out. Rice and rice products of0.001%genetically modified rice were used in this experiment. Under the optimal combination of sample pretreatment,24copies of DNA in each sample was extracted in duplicate, each DNA do two PCR repeats, a total of48PCR repeats. Statistics show that final detection rate of exogenous genes CaMV35S, NOS and Cry1Ab/c is95.80%., which shows that sample instructions before treatment have significant effects on the final detection effect.