Abstract:

The complexity of the feed sample brings great pressure and challenges to the detection of genetically modified (GM） components of imported and exported products. Corn gluten meal mainly contains protein， starch and lipid， etc.， it is difficult to extract high?quality DNA from them. High?quality DNA is the key to GM testing research， which can reduce "false negative" results rates in imported and exported inspection. Seven commercially available kits（Promega Corporation， Biotecon Corporation， Tiangen Biochemical Technology Co.， Invitrogen Corporation， Qiagen Corporation， TaKaRa Corporation）， CTAB method and modified SDS?CTAB method were used to extract DNA from corn gluten meal in this study. The quality of DNA extracted from maize protein flour by the modified SDS?CTAB method was found to be significantly better than the other two methods by real?time fluorescence PCR， and the C_tvalue of the endogenous gene zSSIIb by the modified SDS?CTAB method was 28.14， which was 27% higher than that of the CTAB method. It is the first application of modified SDS?CTAB method in GM feed production at home and abroad. Seven batches of laboratory samples sent by this extraction method were tested for GM components， the results showed that two batches of positive samples were successfully detected.

Key words: corn gluten meal, DNA extraction, real?time fluorescence PCR

摘要：

饲料样本本身的复杂性给进出口产品转基因（genetically modified，GM）成分的检测工作带来了巨大的压力和挑战。玉米蛋白粉主要包含蛋白质、淀粉和脂类等成分，从中提取高品质的DNA比较困难，而高品质的DNA是转基因检测研究的关键，能够大大降低进出口检验中的“假阴性”结果。采用市售主流品牌常用的7种试剂盒（Promega公司、Biotecon公司、天根生化科技有限公司、Invitrogen公司、Qiagen公司、TaKaRa公司）、CTAB法以及改良SDS?CTAB法提取玉米蛋白粉中的DNA。通过对玉米内源基因进行实时荧光PCR检测，发现改良SDS?CTAB法提取的玉米蛋白粉DNA质量明显优于其他方法，改良SDS?CTAB法内源基因zSSIIb的C_t值为28.14，较CTAB法提高了27%。研究建立的改良SDS?CTAB法在国内外尚属首次应用于饲料转基因产品中，并对7批次实验室送检样品进行转基因成分检测，成功检出2批次阳性样品。

关键词: 玉米蛋白粉, DNA提取, 实时荧光PCR