The microbial terroir of the Greek olive varieties

The microbial terroir of Greek olive varieties remains underexplored. In this study, 62 samples of olive fruits, collected during the ripening stage across the period 2019-2020, were analyzed by high-throughput sequencing. These samples represented 38 olive varieties along 9 different ?macrearee of Greece. Analysis of the bacterial composition revealed that the geographical area was a significant factor in discriminating samples. The core microbiota included Erwinia, Pseudomonas, and members of the Enterobacteriaceae family. Furthermore, a notable variation in bacterial taxa abundances associated with the geographic location was observed. The sampling area was a key discriminant factor for the mycobiota, and the core mycobiota consisted in Alternaria, Taphrina, Candida, Wickerhamomyces anomalus and Penicillium. Finally, Redundancy Analysis (RDA) analysis revealed a notable association between environmental characteristics and microbial composition. Specifically, tree age was associated with certain bacterial and fungal taxa (Pearson’s correlation p-value adj.[FDR] < 0.05).