Stilbenes, as important secondary metabolites of grapevine, represent central phytoalexins and therefore constitutean important element of basal immunity. In this study, potential genetic variation ...in Vitis vinifera ssp. sylvestris, theancestor of cultivated grapevine, was sought with respect to their output of stilbenes and potential use for resistancebreeding. Considerable variation in stilbene inducibility was identified in V. vinifera ssp. sylvestris. Genotypic differencesin abundance and profiles of stilbenes that are induced in response to a UV-C pulse are shown. Two clustersof stilbene ‘chemovars’ emerged: one cluster showed quick and strong accumulation of stilbenes, almost exclusivelyin the form of non-glycosylated resveratrol and viniferin, while the second cluster accumulated fewer stilbenes andrelatively high proportions of piceatannol and the glycosylated piceid. For all 86 genotypes, a time dependence ofthe stilbene pattern was observed: piceid, resveratrol, and piceatannol accumulated earlier, whereas the viniferinswere found later. It was further observed that the genotypic differences in stilbene accumulation were precededby differential accumulation of the transcripts for chalcone synthase (CHS) and stilbene-related genes: phenylalanineammonium lyase (PAL), stilbene synthase (StSy), and resveratrol synthase (RS). A screen of the population withrespect to susceptibility to downy mildew of grapevine (Plasmopara viticola) revealed considerable variability. Thesubpopulation of genotypes with high stilbene inducibility was significantly less susceptible as compared with lowstilbenegenotypes, and for representative genotypes it could be shown that the inducibility of stilbene synthase byUV correlated with the inducibility by the pathogen.
Stilbenes, as important secondary metabolites of grapevine, represent central phytoalexins and therefore constitutean important element of basal immunity. In this study, potential genetic variation ...in Vitis vinifera ssp. sylvestris, theancestor of cultivated grapevine, was sought with respect to their output of stilbenes and potential use for resistancebreeding. Considerable variation in stilbene inducibility was identified in V. vinifera ssp. sylvestris. Genotypic differencesin abundance and profiles of stilbenes that are induced in response to a UV-C pulse are shown. Two clustersof stilbene ‘chemovars’ emerged: one cluster showed quick and strong accumulation of stilbenes, almost exclusivelyin the form of non-glycosylated resveratrol and viniferin, while the second cluster accumulated fewer stilbenes andrelatively high proportions of piceatannol and the glycosylated piceid. For all 86 genotypes, a time dependence ofthe stilbene pattern was observed: piceid, resveratrol, and piceatannol accumulated earlier, whereas the viniferinswere found later. It was further observed that the genotypic differences in stilbene accumulation were precededby differential accumulation of the transcripts for chalcone synthase (CHS) and stilbene-related genes: phenylalanineammonium lyase (PAL), stilbene synthase (StSy), and resveratrol synthase (RS). A screen of the population withrespect to susceptibility to downy mildew of grapevine (Plasmopara viticola) revealed considerable variability. Thesubpopulation of genotypes with high stilbene inducibility was significantly less susceptible as compared with lowstilbenegenotypes, and for representative genotypes it could be shown that the inducibility of stilbene synthase byUV correlated with the inducibility by the pathogen.
