Screening for genetically modified tomatoes & tomato seeds and identification of CRY1AC and SAM-K specific modifications using gene and construct specific PCR

Uçkun, Esra
This study was carried out to analyze tomato samples and tomato seeds, purchased from different food markets of Turkey randomly, for the presence of genetic modification by using PCR method as it allows more specific detection. The DNAs of collected samples were isolated according to CTAB DNA extraction protocol and also with extraction kits. Screening tests of tomatoes were done by targeting 35S promoter, NOS terminator and NptII kanamycin resistance gene with eight different primer sets. Real time PCR is used to confirm 35S and NOS positives results obtained from conventional PCR. In this study, it was observed that 14 out of 35 seed samples, and 14 out of 40 fresh tomato samples which were screened had at least one transgenic element of 35S promoter, NOS terminator and NPTII kanamycin resistance gene indicating the possible presence of genetic modifications. After screening, gene specific studies were carried out for PG, sam-k indicating F type ripening delayed tomato and the 35 1 N lines respectively and cry1Ac genes inserted in 5345-1 insect resistant tomato line. PG and sam-k specific primers were not amplified in any of the samples investigated whereas 18 out of 75 samples were cry1Ac positive and 1 out of 75 samples was sam-k positive. Positives were confirmed by sequence analysis. Additionally, construct specific primers specific to 5345-1 and 35 1 N lines were designed. PCR amplicons indicate the existence of the construct sequence. In order to verify the results, PCR products were sent to sequence analysis


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Citation Formats
E. Uçkun, “Screening for genetically modified tomatoes & tomato seeds and identification of CRY1AC and SAM-K specific modifications using gene and construct specific PCR,” M.S. - Master of Science, Middle East Technical University, 2007.