THE FIREFLY LUCIFERASE GENE AS A NONINVASIVE REPORTER FOR DENDROBIUM TRANSFORMATION

Here a screening method is described for transformed tissues and trans genic plants of Dendrobium (Orchidaceae) using the firefly luciferase gene (luc) as a combined marker/reporter gene. Protocorm-like-bodies ( PLB) were bombarded with tungsten particles (1.3 mu m) coated with pla smids carrying a 35S-luc chimeric gene. Three weeks after bombardment 1 mM luciferin was added to the tissues and transformed cells were ide ntified by virtue of their bioluminescence as monitored by low-light v ideo microscopy in combination with a real-time photon imaging techniq ue. Transformed tissues were excised, allowed to proliferate, and then subjected to a second round of screening. After three rounds of growt h and screening, transformed Dendrobium tissues expressing luciferase were used to generate transgenic plants. Southern blot analysis of sev eral transgenic lines confirmed the integration of the luciferase gene into the orchid genome. It is thought that this procedure can be used for transformation of not only orchids but other species as well.