Characterization of a novel stilbene synthase promoter involved in pathogen- and stress-inducible expression from Chinese wild Vitis pseudoreticulata.

Stilbene synthase is a plant-specific polyketide synthase, and plays important roles in diverse metabolic processes. The genomic stilbene synthase gene was cloned from accession "Baihe-35-1" of Chinese wild Vitis pseudoreticulata, and a stilbene synthase of V. pseudoreticulata (VpSTS) transcripts expressed in the grape-powdery mildew interaction were determined by semi-quantitative RT-PCR. To monitor VpSTS expression in plant, the promoter region flanking the 5' VpSTS coding region was isolated from the genomic DNA of Chinese wild V. pseudoreticulata accession Baihe-35-1. Alignment of the VpSTS promoter sequence showed a 56.4% identity to Vitis vinifera. To identify the upstream region of the VpSTS gene required for promoter activity, a series of VpSTS promoter deletion derivatives was constructed. Each deletion construct was analyzed by Agrobacterium-mediated transient transformation in grapevine and tobacco leaves after infection by Uncinula necator and Alternaria alternata. In transiently transformed grapevine leaves, GUS activity was also determined after treatment with salicylic acid (SA) and 4 degrees C cold. Analysis of a series of 5' deletions of the VpSTS promoter in grapevine leaves indicated that the proximal 162 bp from the transcription initiation site was proved to be necessary for establishing both the constitutive and induced pattern of expression.