The host-associated microbiota is involved in health issues of the host this was shown for humans and plants as well ( Derrien and van Hylckama Vlieg, 2015 Berg et al., 2017). Although this amount was the same, the bacterial composition was significantly different in conventionally and organically produced apples. Our results suggest that we consume about 100 million bacterial cells with one apple. Among them, especially bacterial signatures known for health-affecting potential were found to be enhanced in conventionally managed apples. In addition, despite the similar structure in general dominated by Proteobacteria (80%), Bacteroidetes (9%), Actinobacteria (5%), and Firmicutes (3%), significant shifts of almost 40% of bacterial genera and orders were monitored. Abundances were not influenced by the management practice but we found a strong reduction in bacterial diversity and evenness in conventionally managed apples. In all, approximately 10 8 16S rRNA bacterial gene copy numbers were determined in each g apple. Interestingly, fruit pulp and seeds were bacterial hot spots, while the peel was less colonized. Each apple fruit harbors different tissues (stem, peel, fruit pulp, seeds, and calyx), which were colonized by distinct bacterial communities.

We analyzed the apple microbiome to detect differences between tissues and the impact of organic and conventional management by a combined approach of 16S rRNA gene amplicon analysis and qPCR, and visualization using fluorescence in situ hybridization and confocal laser scanning microscopy (FISH-CLSM).

They represent a source of direct human exposure to bacterial communities, which is less studied. Apples are among the most consumed fruits world-wide.

Blue apples to eat