Transformation by Ultrasonication for Gene Transfer - In wheat, tobacco and sugarbeet, explants after being cultured for a few days, were sonicated with plasmid DNA (carrying marker genes like cat, npt II and gus).

When sonicated calli were transferred to selective medium, shoots were obtained, although all control calli (not sonicated with plasmid DNA) died. In tobacco transgenic plants were obtained at a frequency of 22 per cent. This work was conducted at the Biotechnology Research Center at Beijing (China).