title: Interlaboratory validation study of an event-specific real-time polymerase chain reaction detection method for genetically modified 55-1 papaya.
abstract: Genetically modified (GM) papaya line 55-1 (55-1) is resistant to papaya ringspot virus infection, and is commercially available in several countries. A specific detection method for 55-1 is required for mandatory labeling regulations. An event-specific real-time PCR method was developed by our laboratory. To validate the method, interlaboratory validation of event-specific qualitative real-time PCR analysis for 55-1 was performed in collaboration with 12 laboratories. DNA extraction and real-time PCR reaction methods were evaluated using 12 blind samples: six non-GM papayas and six GM papayas in each laboratory. Genomic DNA was highly purified from all papayas using an ion-exchange column, and the resulting DNA sample was analyzed using real-time PCR. Papaya endogenous reference gene chymopapain (CHY) and the event-specific 55-1 targeted sequence were detected in GM papayas whereas CHYalone was detected in non-GM papayas in all laboratories. The cycle threshold values of CHYand the 55-1 targeted sequence showed high repeatability (RSD, 0.6-0.8%) and reproducibility (RSDR 2.2-3.6%). This study demonstrates that the 55-1 real-time PCR detection method is a useful and reliable method to monitor 55-1 papaya in foods.
authors.affiliation: National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Noguchi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nakamura
authors.forename: Kozue
authors.initials: K
authors.lastname: Sakata
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akiyama
authors.forename: Kazunari
authors.initials: K
authors.lastname: Kondo
authors.forename: Reiko
authors.initials: R
authors.lastname: Teshima
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Ohmori
authors.forename: Masaki
authors.initials: M
authors.lastname: Kasahara
authors.forename: Reona
authors.initials: R
authors.lastname: Takabatake
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kitta
mesh_terms: D029441:Carica / Q000235:genetics*; D018744:DNA, Plant / Q000302:isolation & purification; D030841:Food, Genetically Modified; D030821:Plants, Genetically Modified / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*
chemical_list: D018744:DNA, Plant