Features of basidiomycetous yeasts from grapes and apples associated with crop environment and fermenting juice.

AIMS: The characterization of grape and apple yeasts was carried out to investigate the ecology of basidiomycetes associated with crop environment and fermenting juice. METHODS AND RESULTS: A total of 15 basidiomycetous strains were analysed for plant-growth promoting properties, sensitivity to fungicides and features related to their survival in fermenting juice (low pH, SO2 and ethanol sensitivity). Only one strain displayed 1-aminocyclopropane-1-carboxylate deaminase activity, whereas other strains were able to produce ammonia and indole-3-acetic acid, solubilize calcium phosphate, and display catalase activity and antagonism against Botrytis cinerea. Strains presented great variability in their sensitivity to fungicides. Rhodotorula mucilaginosa Yl26 and Sporobolomyces agrorum PYCC 8108T displayed low sensitivity to all fungicides, with high tolerance to SO2 and ethanol, and were able to survive in fermenting grape and apple juice. CONCLUSIONS: This study revealed the diversity of basidiomycetous yeasts in the important physiological traits that affect their growth, either in the crop environment or in fermenting juice. SIGNIFICANCE AND IMPACT OF THE STUDY: Identify the possibility of selective effects of fungicide treatments on basidiomycetous yeasts that could offer benefits for grapevines and apple trees, as well as the survival of strains that are better adapted to fermenting juice and that potentially have a role in the aroma of beverages.