Microbial communities of sweet cherry (Prunus avium L.) and assessment of their association with cherry slip-skin-maceration disorder

Abstract A relatively new condition of sweet cherry (Prunus avium L.), cherry slip-skin-maceration disorder (cherry-SSMD), presumably associated with yeast species, required a detailed study looking at the microbial communities inhabiting the fruit and blossoms of commercial cherry trees. Cherry-SSMD affects the fruit quality of mainly late harvest sweet cherries and may lead to symptom development that is associated with one or more different, but typically non-pathogenic yeast species. These symptoms may be the result of significant shifts within the fruit’s normal microbiota, and may in turn be influenced by tree fruit phenology and/or environmental factors relating to variable harvest dates. Therefore, the main objective of this study was to conduct field surveys to investigate the microbial species composition on cherry blossoms and fruit. Results obtained from surveys conducted during the 2013 and 2014 growing seasons indicated that while fungal populations remained low, numbers of yeasts and bacteria continued to increase on the surface of developing fruit throughout the growing season. Species composition was also observed to be variable between years and throughout the growing seasons. However, despite general increases in microbial populations of bacteria and yeasts leading up to harvest, no specific pattern was observed to suggest a pathogenic profile that would link either microbial communities, or individual species to cherry-SSMD.