Cereal Research Communications

, Volume 35, Issue 3, pp 1375–1383 | Cite as

Characterization of Left-border Flanking Sequences of T-DNA Integration in Transgenic Rice (Oryza sativa L.) Expressing cry1Ab

  • M. A. Zaidi
  • X. Y. Cheng
  • I. AltosaarEmail author
Open Access


To understand the molecular details of T-DNA integration, the left border (LB) sequences and flanking plant DNA of 16 independent T-DNA insertions in transgenic cry1Ab rice were analyzed by an inverse PCR approach. DNA sequencing indicated that five of the 16 fragments (31%) were found to have simple or rearranged tandem repeats of right border sequences in a head to tail fashion. Mirror truncations of LB of the T-DNA, as well as mirror rearrangements, such as point mutations, small deletions and inversions were found in the region close to the LB breakpoints in some inserts. Host plant DNA flanking the T-DNA endpoints were also sequenced. The A+T contents in the plant DNA within 50 bp adjacent to the T-DNA endpoints were between 30–76% (average 52.5%), not different from the average genome value. Despite minor mutations and some rearrangements, it appears that T-DNA, harbouring a synthetic cry1Ab coding sequence of 49% GC (as well as uidA and hph), still carries such a foreign gene into ‘transcriptionally active regions’ of the rice genome, which are 55.8% GC on average as predicted from the rice genome sequence.


rice cry1Ab Agrobacterium T-DNA left-border right-border repeat DNA sequence promoter 


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© Akadémiai Kiadó, Budapest 2007

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  1. 1.Agricultural Biotechnology Laboratories, Department of Biochemistry, Microbiology and ImmunologyUniversity of OttawaOttawaCanada
  2. 2.Syngenta Biotechnology, Inc.Research Triangle ParkUSA
  3. 3.Proteins Easy Corp.OttawaCanada

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