Event-specific qualitative and quantitative detection of transgenic rice Kefeng-8 by characterization of the transgene flanking sequence

The transgenic rice line Kefeng-8 harboring insect-resistant genes Cry1Ac and CpTI showed ideal field performances characterized by high resistance to rice stem borer (Scirpophaga incertulas) and leaf roller (Cnaphalocrocis medinalis). This GM rice line is likely to be approved in China in the near future. In this study, we estimated the insert number of foreign genes, analyzed the flanking sequences of T-DNA in rice genome, and presented an event-specific detection method for this line. The results show that the foreign gene inserted one copy between position 11,774 and 11,805 of chromosome 11 (AC120536.5) in Kefeng-8 genome. Based on these inserts and border sequences, the event-specific qualitative and quantitative PCR system was established for Kefeng-8. The qualitative detection limit was assessed to be 0.1%, and the limit of quantitative method was assessed to be 100 initial template copies. Two mixed rice sample with known Kengfeng-8 contents were used to verify the quantitative method, from which the expected results were observed. This study provides a reliable method and information for detection, identification, and quantification of the presence of GM rice Kefeng-8.