Principal Investigators: Patricia Okubara, plant pathologist
USDA-Agricultural Research Service
Washington State University, Pullman WA
Summary: Native yeasts are of increasing interest to researchers, grape growers and vintners because of their potential for biocontrol activity and their contributions to the aroma, flavor and mouthfeel qualities of wines. To assess biocontrol activity, we tested 11 yeasts from Washington vineyards for their ability to colonize Thompson Seedless grape berries, inhibit the growth of Botrytis cinerea in vitro, and suppress disease symptoms on isolated berries.
All yeast strains multiplied rapidly in grape berries and reached densities of over log 6 cells per wound as early as 2 days after inoculation with 200 cells. Inhibition of Botrytis isolates by the yeast strains was more common on berries than in vitro, suggesting the possibility that niche competition was a more likely biocontrol mechanism than antibiosis in plant. Metabolic profiling of yeast strains and Botrytis revealed seven distinct metabolic groups. The yeast strains showed partial to complete tolerance to several commonly used fungicides.
A full report from this report published in Phytopathology can be downloaded above.