Green fluorescent protein as an all-purpose reporter in Petunia

Two critical attributes of a reporter gene are ease of scoring for activity and capacity for expression in all cell types. We have examined a variant of the gene encoding green fluorescent protein,mgfp5, for its ability to meet these criteria in petunia. Under regulation of the Cauliflower Mosaic Virus (CaMV) 35S promoter, GFP was detectable in all vegetative and most floral cell types. Promoters from petuniaadhl andadh2 allowed for production of GFP in those few cell types lacking GFP production from the CaMV 35S promoter, verifying its capacity for expression in all cell types. With the appropriate promoter, GFP fluorescence was thus readily detectable throughout the plant. A potential complication is the green autofluorescence exhibited by some plant tissues. This auto-fluorescence is for the most part distinguishable from that contributed by GFP, but under-scores the need for appropriate controls in GFP-reporter-based experiments.