Monitoring adventitious presence of transgenes in ex situ okra (Abelmoschus esculentus) collections conserved in genebank: a case study
2016
Bairwa, Rakesh Kumar | Singh, Monika | Bhoge, Rajesh K. | Devi, Chitra | Randhawa, Gurinderjit
The National Gene Bank at ICAR-National Bureau of Plant Genetic Resources, New Delhi, second largest genebank in the world, conserves more than 0.4 million accessions, including 3434 accessions of okra. Wild and weedy relatives of crops are being conserved as ex situ collections in the genebanks or on farm in the diversity-rich delicate pockets. To ensure GM-free conservation of the germplasm, unintentional introgression of transgenes needs to be monitored. In India, field trials of Bt okra with cry1Ac gene at Biosafety Research Levels-I and II were conducted by Maharashtra Hybrid Seeds Company Limited during 2006–2007. For preliminary study, adventitious presence of transgenes in 50 okra accessions of conserved ex situ collections was undertaken. A two step-approach was employed, first step comprising screening assays targeting Cauliflower Mosaic Virus 35S (CaMV 35S) promoter and Agrobacterium tumefaciens nos terminator using singleplex Polymerase Chain Reaction (PCR) and real-time PCR assays; followed by the second step employing gene-specific assay targeting cry1Ac gene. Based on the present study, no adventitious presence of transgenes was detected in tested samples. The present study would be efficient and reliable approach for monitoring adventitious presence or unintentional introgression of transgenes in larger collections of okra and in collections of other crops, e.g., eggplant, rice, exhibiting rich diversity, where field trials of respective GM crops are being conducted in close proximity of their wild and weedy relatives.
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