The GUS reporter system in flower development studies.

The β-glucuronidase (GUS) reporter gene system is an important technique with versatile uses in the study of flower development. Transcriptional and translational GUS fusions are used to characterize gene and protein expression patterns, respectively, during reproductive development. Additionally, GUS reporters can be used to map cis-regulatory elements within promoter sequences and to investigate whether genes are regulated posttranscriptionally. Gene trap/enhancer trap GUS constructs can be used to identify novel genes involved in flower development and marker lines useful in mutant characterization. Flower development studies primarily have used the histochemical assay in which inflorescence tissue from transgenic plants containing GUS reporter genes are stained for GUS activity and examined as whole-mounts or subsequently embedded into wax and examined as tissue sections. In addition, quantitative GUS activity assays can be performed on either floral extracts or intact flowers using a fluorogenic GUS substrate.