Polymerase Chain Reaction Detection of the Modified cry1Ac Gene in Transgenic Bt (Bollgard®) Cotton

Transgenic cotton (Gossypium hirsutum L.) containing a modified cry1Ac gene from the soil bacterium Bacillus thuringiensis Berliner has been widely adopted for suppression of lepidopterous pests. As of 2004, over 90% of the cotton acreage in the mid-southern United States contained this modified cry1Ac gene. We developed a technique using the polymerase chain reaction (PCR) for routine detection of the cry1Ac gene in transgenic cotton plants. A total of eight cry1Ac genes were aligned for the PCR primer design. A DNA fragment was amplified from transgenic cotton, sequenced, and confirmed to be a portion of the cry1Ac gene. A total of 150 cotton plants representing four cultivars were examined for the presence of the cry1Ac gene. Results demonstrated that all of these cotton plants harbored the cry1Ac gene (i.e., 100% purity). This PCR technique can be used for future studies involving the expression of cry1Ac gene as well as corresponding protein expression.