Integration and characterization of T-DNA insertion in upland cotton

Abstract

Copy numbers were evaluated by real-time quantitative PCR, and 149 junctions of T-DNA were isolated by thermal asymmetric interlaced PCR from 92 independent transgenic cotton lines transformed by Agrobacterium tumefaciens strain LBA4404. Real-time quantitative PCR results showed that 46% had integration of one or two T-DNA copies, 54% had three or more copies. Among 63 amplified products at LB junctions, 51% showed co-transformation of the vector backbone, 30% retained a portion of LB ranging from 3 to 23 bp, and 19% showed deletions ranging from 1 to 148 bp from the LB inner end. In contrast, all of the cleavage sites were located in the inner region of RB. The distribution of T-DNA insertions in upland cotton genome included coding sequences, transposons, plastid-derived sequences and microsatellites.