EXPRESSION OF RECOMBINANT RENILLA LUCIFERASE IN TRANSGENIC PLANTS RESULTS IN HIGH-LEVELS OF LIGHT-EMISSION

A 970 bp DNA fragment which encodes the luciferase enzyme of the marine soft coral Renilla reniformis was fused to the cauliflower mosaic virus (CaMV) promoter. The construct pPCV702-ruc was transferred into alfalfa protoplasts by Ca-PEG-mediated transformation and into tobacco, tomato and potato plants by Agrobacterium-mediated transformation. The light emission from homogenates of alfalfa protoplasts transformed with pPCV702-ruc was 16-fold higher than that of protoplasts transformed with the same vector carrying the bacterial luxF gene. Application of a 3 mu M aequous solution of 2-benzyl luciferin (luciferin) on to calli, leaves, roots and slices of tomato fruits and potato tubers of transformed plants resulted in strong light emission within seconds which could be easily visualized by a photon counting camera. Light emissions obtained from tissue homogenates of tobacco plants containing a single copy of the pPCV702-ruc construct were around ttl-fold higher than those from plants carrying multiple copies of the firefly luciferase gene and around 360-fold higher than those from plants transformed with the bacterial luciferase gene. Owing to its high efficiency the Renilla luciferase may become a useful and novel tool for gene expression studies in plants and other systems.