Pear fruits host diverse microbial communities that influence postharvest quality, spontaneous fermentation, and susceptibility to microbial contamination. This study characterizes the fungal communities associated with naturally fallen overripe pears (Pyrus communis) using ITS2 amplicon sequencing combined with culture-dependent approaches. The fungal community exhibited low diversity and was dominated by Ascomycota (99%), primarily Saccharomycetes (91.8%), with Hanseniaspora, Aureobasidium, and Microcyclospora representing more than 90% of the total microbial community. Culture-dependent isolation confirmed Hanseniaspora uvarum as the dominant yeast species (~89%), followed by Metschnikowia spp. and Pichia spp. Pairwise co-culture assays, quantified using the Relative Interaction Index, demonstrated predominantly competitive interactions, with fast-growing H. uvarum exerting suppressive effects on slower-growing species. Among the isolated yeasts, Metschnikowia fructicola exhibited antibacterial activity against all tested bacteria Staphylococcus aureus, Listeria innocua and Salmonella typhimurium. The strongest antibacterial activity was exerted against the foodborne pathogen S. aureus. In a pear juice model system, co-cultivation with M. fructicola resulted in the elimination of S. aureus within four days, while yeast viability was maintained. These findings observe the fermentative yeasts distributed in overripe pears and demonstrate the potential of M. fructicola to inhibit bacterial growth under controlled conditions. The results provide a preliminary basis for further studies on fungal succession, yeast interactions, and the biocontrol potential of pear-associated yeasts. For broader ecological conclusions, larger-scale studies across locations, seasons, cultivars, and decay stages are required.
Vepštaitė-Monstavičė et al. (Sun,) studied this question.