Decreased diversity and connectivity of endophytic fungal assemblages within cultivated European olive trees compared to their native African counterpart

Host identity and location help shape fungal endophyte assemblages in plants. Hosts act as uptake filters from the environment and closely related hosts in the same location may harbour similar assemblages. We assessed the influence of host identity and geographic location on endophytic fungal assemblages within the native African olive and cultivated European olive in South Africa using high throughput sequencing. As hypothesised, the two hosts were found to share many endophytic species, but alpha diversity was lower within the European olive. The two hosts had significantly dissimilar endophyte assemblages. Distance between sites positively correlated with endophyte assemblage dissimilarities, demonstrating a strong effect of the surrounding environment on endophyte assemblages. African olive individuals had highly connected endophyte assemblages, unlike those within the European olive. Microbiome sharing and disconnected assemblages may have negative impacts on the health of the cultivated host.