VERSATILE TRANSFORMATION VECTORS TO ASSAY THE PROMOTER ACTIVITY OF DNA ELEMENTS IN PLANTS

A convenient vector system was developed to evaluate transcriptional p romoter activities in plants. Two primary vectors, optionally containi ng the cauliflower mosaic virus (CaMV) 35S -47 or -90 minimal promoter s, offer multiple sites for cloning the sequence of interest upstream from the beta-glucuronidase gene (gusA). The promoter-gusA cassette ca n be transferred to a binary vector containing the selectable neomycin phosphotransferase II-encoding gene (nptII) next to the left border. In addition, the transferred DNA (T-DNA) contains the chloramphenicol acetyltransferase gene (cat) driven by the CaMV 35S promoter. Activity of cat can serve as a reference for gusA expression to correct for ef fects of chromosomal position or T-DNA copy number.