DISEASE RESISTANCE RESULTS FROM FOREIGN PHYTOALEXIN EXPRESSION IN A NOVEL PLANT

ALTHOUGH phytoalexins1,2 have long been inferred to be important in the defence of plants against fungal infection1,2, there are few reports showing that they provide resistance to infection. Several plants, including grapevine, synthesize the stilbene-type phytoalexin resveratrol3-7 when attacked by pathogens. Stilbenes with fungicidal potential are formed in several unrelated plant species, such as peanut (Arachis hypogaea), grapevine (Vitis vinifera) and pine (Pinus sylvestris)3,5,11-15. Stilbene biosynthesis only specifically requires the presence of stilbene synthase 6,9. Furthermore, the precursor molecules for the formation of hydroxystilbenes are malonyl-CoA and p-coumaroyl-CoA, both present in plants9. To investigate the potential of stilbene biosynthetic genes in a strategy of engineering pathogen resistance, we isolated stilbene synthase genes from grapevine, where they are expressed at a high level, and transferred them into tobacco10. We report here that regenerated tobacco plants containing these genes are more resistant to infection by Botrytis cinerea. This is, to our knowledge, the first report of increased disease resistance in transgenic plants based on an additional foreign phytoalexin.