DNA-based diagnostics for genetically modified cotton: decaplex PCR assay to differentiate MON531 and MON15985 Bt cotton events.

The adoption rate and global area under cultivation of genetically modified (GM) crops is dramatically increasing in recent past. GM cotton has occupied 25.0 million hectares (mha) comprising 15.6% of the global area under GM cultivation. Bt cotton, expressing delta-endotoxins from Bacillus thuringiensis (Bt), is the only commercialized crop in India that is planted on an area of 10.6 mha. With the increase in development and commercialization of GM crops, it is necessary to develop appropriate qualitative and quantitative methods for detection of different GM events. Robust diagnostics for GM detection need to be developed and implemented to monitor and detect different events of GM cotton in India. This chapter summarizes the methods based on polymerase chain reaction (PCR) being employed for detection of different GM events of cotton. We describe a decaplex PCR method for identification and differentiation of two major commercialized events of Bt cotton, i.e., MON531 and MON15985, in India.