Investigating the spatiotemporal dynamics of apple tree phyllosphere bacterial and fungal communities across cultivars in orchards

This study investigated the determinants of the spatiotemporal variation in bacterial and fungal communities within the apple phyllosphere, employing 16S and ITS amplicon sequencing. Our research assessed the impact of key factors (plant compartment, site, time, and cultivar) on the composition and diversity of leaf and flower microbial communities. Our analyses based on data collected in three orchards in 2022 revealed that site and time are the strongest drivers of apple tree phyllosphere microbial communities. Conversely, plant compartment and cultivar exhibited minor roles in explaining community composition and diversity. Predominantly, bacterial communities comprised Hymenobacter and Sphingomonas, while the most relatively abundant fungal genera included Aureobasidium and Sporobolomyces. Additionally, our results show a gradual decrease in alpha-diversity throughout the growth season. These findings yield valuable insights as many groups worldwide aim for the development of biocontrol strategies, emphasizing the necessity to consider local microbial ecology dynamics. This work entails a deeper exploration of the determinants of time and site-specific disparities within three apple cultivars phyllosphere microbial communities.