Ethylene- and ozone-induced regulation of a grapevine resveratrol synthase gene: different responsive promoter regions

Stilbene synthases (STSs) are enzymes that play a critical role in the biosynthesis of stilbenes, phytoalexins that are induced by various biotic and abiotic stressors like pathogen attack, UV radiation or ozone exposure. To investigate the molecular basis for ozone- and ethylene-induced plant stress responses, we analysed the full size promoter of the grapevine resveratrol synthase gene (Vst1). Transgenic tobacco plants harbouring a Vst1 promoter::β-glucuronidase (GUS) reporter construct showed an increased GUS activity upon ozone (0.3 μl l–1, 8 h) or ethylene (10 μl l–1, 8 h) treatment. Using the fluorimetric GUS assay, deletion analysis of the 5′-flanking sequence identified a minimal ethylene-responsive region between –280 and –40 bp upstream of the translation start codon. This region differs from the ozone-responsive Vst1 promoter region, suggesting that ethylene is not directly involved in signalling ozone-induced stilbene biosynthesis.