Abstract: Adenosine deaminase gene (ADA gene) is used as a selectable/reporter gene for plant cells and plants. When introduced into plant cells, the ADA gene makes the cells resistant to inhibition by 2-deoxyadenosine or an analog, so transformed cells can be separated from non-transformed cells by culturing a cell mixture in a medium containing 2-deoxyadenosine or an analog in amounts that inhibit normal plant cells. A single vector may be constructed containing an ADA gene from any source (e.g. a mouse ADA gene) and an additional gene-of-interest to be introduced into plant cells. The vector may then be introduced into the cells by such a route as Agrobacterium infection or micro-projectile bombardment. The presence of the ADA gene in successfully transformed plant cells may be confirmed by cultivating the cells in a medium containing 2-deoxyadenosine or an analog in the presence of a material that changes color in the presence of ammonia. Observation of a color change confirms the presence of the gene.