Effect of Marker Gene Location in T-DNA on Gene Transfer from Agrobacterium to Plant Cells

Authors: Sebahattin ÖZCAN

Abstract: The present paper describes whether the efficiency of gene transfer from Agrobacterium tumefaciens to plant cells is influenced by the location of npt-II marker gene in T-DNA region. Therefore, binary vectors pSCV-Ori1 and pSCV-Ori2 were constructed and used for tobacco leaf disc transformation. pSCV-Ori1 harboured the npt-II marker gene adjacent to left border but 2.3 kb away from the right border, whereas pSCV-Ori2 contained the npt-II gene placed next to right border. Transformation experiments showed that pSCV-Ori2 plasmid resulted in higher frequency of kanamycin resistant callus clusters and shoots than pSCV-Ori1. This result clearly indicates that when the marker gene is placed adjacent to right border, it is transferred to plant cells more efficiently. However, cloning the marker gene a further 2.3 kb away from the right border reduced the transformation frequency. Integration of the marker gene into the tobacco genome was confirmed by PCR.

Keywords: Agrobacterium tumefaciens, transformation, T-DNA, right border, npt-II gene