Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2007
Publication Date: N/A
Technical Abstract: Although all high quality Vitis vinifera cultivars are highly susceptible to powdery mildew, current efforts show promise for the identification or modulation of resistance within the species and for continued introgression of resistance from resistant accessions of wild Vitis spp. Examination of the plant-fungus interaction at a microscopic level provides insight into the mechanistic nature of resistance as well as its genetic action and potential durability. In this study, a panel of wild accessions representing potential sources of resistance was inoculated with a single isolate of powdery mildew, and pathogen growth was monitored by light and confocal microscopy until 3 days post-inoculation (dpi). In addition, disease symptoms were rated at 21 dpi. The V. rotundifolia source of Run1 resistance was effective only after penetration and initial formation of secondary hyphae, while the resistant interspecific hybrid ‘Ill 547-1’ reduced the efficiency of penetration. A susceptible V. rotundifolia accession inhibited neither penetration nor colonization. Data for other accessions will be presented, and important considerations in mechanistic studies will be discussed.