Reporter genes and transient assays for plants.

The introduction of DNA into plant cells, protoplasts, or intact tissue s has been accomplished by a variety of mechanisms, including electropo-ration, electrofusion, particle bombardment, liposome transfer, the us e of bacterial vectors, polyethylene glycol treatment, and other procedures. As new techniques are developed or modified, it is necessary to use a reliable gene-expression system to monitor DNA uptake, transcription , and translation. A series of DNA plasmids containing reporter genes encoding readily assayed enzymes are available for this purpose. Several reporter gene systems have been used in experiments to transform plant s and to perform transient assays with plant material. In_ general, thes e reporter genes encode enzymes whose activities can be detected through assays and stains, thus facilitating the identification of transformed cell s and quantification of the transformation process. Reporter genes also provide a method for analyzing regulatory characteristics of promoters , such as promoter strength and tissue specificity, when the promoter fro m a gene of interest is coupled to the reporter gene. Reporter gene constructs are comprised of a reporter gene togethe r with active promoter and terminator regions cloned into a plasmid vector. Sometimes these constructs lack promoter regions, so different pro