Isolation and PCR Detection of Foreign DNA Sequences in Bee Honey Raised on Genetically Modified Bt (Cry 1 Ac) Cotton

Genetically modified Bt cotton has been planted in large scale in China since 1997. Its acreage reached 3.7 million ha, accounting for 66% of the total cotton cultivation area in 2004. Since cotton is one of the major honey-source plants, it raises a concern in the international trade whether there are any alien DNA sequences contained in honey. Therefore, development of detection methods for bee honey associated with Bt cotton has become urgently needed. We have developed a DNA extraction procedure and a PCR protocol for the detection of foreign DNA sequences in bee honey. A detailed step-by-step procedure for the extraction of DNA from honey was described. A key step for purifying DNA from bee honey is to separate out high amount of sugars by using phosphate buffered saline (PBS) with stronger buffering capacity. With PCR protocol, alien and cotton endogenous DNA sequences with a length of 125–550 bp can be specifically amplified.