Agrobacterium tumefaciens-mediated transformation of modern rose (Rosa hybrida) using leaf-derived embryogenic callus

Rose (Rosa hybrida) is widely used for cut flowers and as garden plants. Stable and efficient transformation system is required for functional genomics of rose. Here, we established an efficient transformation method for rose using Agrobacterium tumefaciens-mediated transformation of embryogenic callus. Expanding rose leaves were used as explants to induce somatic embryos, which were subjected to transformation with A. tumefaciens strain GV3101 using Green Fluorescence Protein (GFP) as a marker gene. It took about 8 months to generate transgenic shoots from embryogenic callus. PCR, RT-PCR, Southern and Western blotting, as well as stereoscopic fluorescence microscopy analysis demonstrated that GFP transgenes integrated stably into the rose genome. According to our data, a transformation efficiency of up to 6% can be achieved by following this optimized protocol.