IRAP Analysis of Transgenic Wheat Plants with a Double-Stranded RNA Suppressor of the Proline Dehydrogenase Gene

Resumo

The polymorphism level of DNA regions flanked by inverted LTR retrotransposon repeats has been analyzed by the IRAP method in genetically modified wheat plants that contained a double-stranded RNA suppressor of the proline dehydrogenase gene and that had been obtained by Agrobacterium-mediated transformation in an in vitro culture. No DNA polymorphism was detected in the transgenic plants when highly efficient primers for Sukkula, Sabrina, Wham, Nikita, and Wilma1 retrotransposons were used. We did not register the disappearance of amplicons in the DNA profiles of PCR in the experiment, and this may be indicative of the absence of rearrangements in the primer annealing sites and in the loci studied. The emergence of new amplicons was not observed in the spectra of DNA amplification products, which is indicative of the absence of activation of the transposon activity of mobile genetic elements in transgenic plants with a double-stranded RNA suppressor of the proline dehydrogenase gene. To expand the spectrum of amplicons in PCR products of the samples studied, we tested a method that involved the combined use of IRAP primers for different retrotransposons in a single reaction. IRAP primer pairs were selected experimentally, but the use of this method did not reveal the disappearance or emergence of polymorphic fragments. The absence of DNA polymorphism in transgenic plants with a double-stranded RNA suppressor of the proline dehydrogenase gene may be due to the phenomenon of RNA interference that suppresses retrotransposon activity.