Abstract
Vital reporters provide the opportunity to measure gene expression in living cells. In this work, we developed a bioluminescent reporter system for monitoring plastid gene expression in tobacco. The firefly luciferase gene driven from the plastid psbA promoter and its 5'-UTR was stably introduced into a region of the tobacco plastid genome by homologous recombination. The transplastomic plants successfully expressed active luciferase enzyme, whose accumulation reached up to 0.5-1% of total cellular soluble proteins. In the transgenic seedlings, bioluminescence derived from luciferase activity was exclusively detected in the photosynthetic tissues, and exhibited robust circadian oscillation under continuous light condition. These results suggest that firefly luciferase should be a useful reporter for detection of plastid gene expression with high spatial and temporal resolution.
