Identification of a novel plant virus promoter using a potyvirus infectious clone.

A putative promoter from the strawberry vein banding caulimovirus (SVBV) genome was identified by its ability to drive infection with full-length cDNA of the zucchini yellow mosaic RNA potyvirus (ZYMV). A high rate of infection was obtained with the cDNA under control of the SVBV promoter using particle bombardment technology. The SVBV promoter shows 60% homology to the cauliflower mosaic virus 35S promoter in the domain spanning the conserved motifs of CCACT (at -83) and the TATA box (at -31), to the transcription start. The 3'-end one-third of the putative promoter (328 bp) was sufficient to invoke full infectivity with the ZYMV clone, and drove transient reporter gene expression in Solanaceae and Cucurbitaceae transformed with a binary plant transformation vector. Stable expression of a reporter gene (GUS) under control of the truncated SVBV promoter was shown in transformed tobacco shoots in roots, leaves and stems.