Luciferase as a Reporter of Gene Activity in Plants

Reporter gene systems based upon modified luciferase genes isolated from organisms, ranging from bacteria to insects, have proven to be important tools for plant molecular studies. The biochemical characteristics of these genes combine very high sensitivity with the ability to determine reporter activity non-destructively in vivo, allowing many applications in plants that cannot be accomplished using any other single reporter system. The relative ease of in situ detection of the firefly luciferase has made it an especially successful reporter for screening mutants in the model plant genetic system, Arabidopsis thaliana. The rapid turnover rate of luciferase has aided the characterization of promoters and elements that are influenced by time-sensitive factors such as circardian rhythm (diurunal cycles), gene silencing, and environmental stresses. The high sensitivity of luciferase as a reporter has facilitated the analysis and development of synthetic promoters for plant gene expression. Additionally, the biochemical characteristics of different luciferases have allowed their use as in situ indicators of metabolic activity and oxygen levels, as well as direct indicators of in vivo protein-protein interaction. The various applications of luciferase-based reporter systems in plants will be the subject of this review.