Deletion analysis of the Sugarcane bacilliform virus promoter activity in monocot and dicot plants

The Sugarcane bacillifonn virus (SCBV) promoter confers strong constitutive expression in both monocot and dicot plants. To further characterize the SCBV promoter, we conducted a deletion analysis to identify cis-acting promoter elements and determine the minimal promoter sequence required for full promoter activity. Sequential deletions of the 5' end of a 1.4 kb SCBV promoter fragment fused to the Escherichia coli gusA reporter gene were used to transiently transform Black Mexican Sweet (BMS) corn (Zea mays L.) suspension culture cells and for the production of transgenic plants of Arabidopsis thaliana and Avena sativa. The results from the BMS cells and the stably transformed Arabidopsis seedlings indicate that the SCBV promoter contains cis-elements affecting promoter strength. Although database searches identified several putative cis-elements that may regulate SCBV promoter specificity, no regions that conferred tissue-specific expression within species were observed except for construct pSCBV-385d which showed constitutive expression in the petals of A. thaliana. Differences were observed in embryo expression between A sativa and A. thaliana. The promoter activity of a fragment beginning at -254 relative to the TATA box was similar to that of the full-length promoter and therefore should be useful for use in transgene expression.