Comparative analysis of the microbiota of <i>Vaccinium myrtillus</i> and <i>Vaccinium uliginosum</i> in the Central Italian Apennines

Vaccinium is a genus of shrubs known for their antioxidant and anti-inflammatory compounds. While the commercially cultivated blueberry ( V. corymbosum ) originates from North America, European species like V. myrtillus (bilberry) and V. uliginosum (bog bilberry) remain uncultivated due to poor adaptability to conventional growing media. At present, bilberries, which are more valued for fresh consumption, are exclusively harvested from wild populations, where unique soil and climate conditions prevail, particularly in subalpine and mountain environments. This study explores the bacterial and fungal communities associated with V. myrtillus and V. uliginosum in wild populations of the Central Italian Apennines, using 16S rRNA and ITS amplicon sequencing. Microbiota from plant and soil were analyzed, revealing distinct microbial community compositions based on species and plant compartments. Bacterial diversity was highest in bulk soil, while fungal diversity dominated plant tissues. Co-occurrence network analysis showed greater connectivity in V. uliginosum microbiota, suggesting higher resilience. Functional predictions indicated roles in nitrogen cycling, cellulose degradation, and plant-microbe interactions. These findings offer insights into the native microbiota of wild Vaccinium species and could be used for conservation and cultivation efforts.