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

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.