Switch on Immunity

New gene switch for basal immunity

In our collection of the European Wild Grape we found some plants that were resistant against a couple of diseases. A specialised form of immunity was unlikely here, because these diseases occur in Europe only for 150 years. We reasoned therefore that, here, the basal immunity was activated more efficiently. In fact we could show that these grapes can activate the formation of the defence compound resveratrol faster and stronger. After subjecting our "champion", a wild grape with the name Hördt 29, to next generation sequencing, it turned out that in this grape a gene switch, MYB14 harboured in its control sequence (the so called promoter) a specific region that was absent in domesticated grapes. This was exciting, because MYB14 binds to the promoter of stilbene synthase, the enzyme that produces resveratrol as central defence compound. Using a somewhat exotic approach we could then demonstrate that this gene stretch from the wild grape was in fact responsible for the more rapid activation of the MYB14-promoter. Herefore, both versions of the MYB14-promoters (one from Hördt 29, the other from domesticated grapes) were fused in front of the gen for luciferase. Luciferase is the enzyme causing the gloom of the firefly. The fusion construct was then shot by means of a gene gun into grapevine cells and then we tested, how the promoter was activated by signals from pathogenic microorganisms - when the promoter is activated, the firefly gloom will tell us, how strong the activation is. In fact, we were able to show that the gene piece from the wild grape Hördt 29 activated around four times stronger, when compared to the corresponding gene variant from domesticated grapes. more...