Wheat Transformation Using Cyanamide as a New Selective Agent

There is a general need for additional selectable marker genes for plant transformation. Only a few have been reported in wheat ( Triticum aestivum L.) transformation experiments, some of which are under patent restriction or have other disadvantages. A new selectable marker gene was identified which can be used to select resistant callus in tissue culture and regenerate transgenic wheat plants. A gene from the soil fungus Myrothecium verrucaria (Albertini & Schwein.) Ditmar:Fr., coding for the enzyme cyanamide hydratase which converts cyanamide into urea, was previously described. In our wheat transformation experiments, the gene conferred resistance to cyanamide at a tissue culture level and therefore cyanamide could be used to select for transformants. At the whole plant level, progeny of transformed wheat plants showed resistance to cyanamide, whereas sensitive plants expressed a lethal necrosis and yellowing when cyanamide was applied. This gene has several potential advantages when compared with other selectable marker genes. Transformed wheat plants can be selected at the tissue culture level and may be able to convert cyanamide into a useful nitrogen compound (fertilizer). The selectable marker gene could be introduced with other genes for value‐added traits in wheat and might also be applicable in other transformation systems.