Analysis of Flanking Sequences of T-DNAs in Transgenic Birch Plants Based on SiteFinding PCR

Long-lived tree mediated by Agrobacterium tumefaciens has technically matured to some extent, but the mechanics of T-DNA integration in transgenic birch (Betula platyphylla) remains largely unknown. Using SiteFinding PCR, we analyzed the flanking sequences of T-DNAs in transgenic birch plants, in which the foreign genes have been integrated stably. Flanking sequence analysis was conducted for the transgenic lines where left and/ or right T-DNA border flanking genomic regions were obtained. A relatively high percentage AT value was found for the flanking regions. The deletion of the right border repeat was observed in the junctions analyzed. The number of nucleotides deleted varied from 3 to 91. Deletions of 17-589 bp were observed in all left T-DNA junctions analyzed. We also report on the presence of vector backbone DNA sequence in transgene loci detected using primer pairs outside the left and right T-DNA borders. Approximately 76. 7% of the lines contained some vector backbone DNA.