Richness of yeast community associated with apple fruits in Estonia

Yeasts are single-celled fungi that are widespread around the globe. They are part of a community of microorganisms that use a wide variety of habitats, including fruit surfaces. This study aimed to characterise the culturable epiphytic yeasts associated with apple fruits. The isolated yeast strains were identified by sequencing the 5.8S-ITS region and D1/D2 region of the large subunit ribosomal RNA gene and maintained for long-term storage. A total of 230 yeast isolates belonging to 33 species were recovered. Most of the collected isolates belonged to the phylum Basidiomycota. Members of genera Vishniacozyma, Filobasidium, and Rhodotorula were most frequently isolated. Over half of the species were isolated on only one to three occasions. In seven of the species obtained, the isolates were considerably divergent from their closest relatives and may therefore represent new distinct species. The results of this study demonstrate a high diversity of yeast species associated with apple fruits.