Clermontia phyllosphere

DNA banks are used as storage repositories for genetic diversity of organisms ranging from plants to insects to mammals throughout the world. These banks provide preserve the genetic information for organisms of interest, however they also indirectly preserve organisms’ associated microbiomes, such as the fungi associated with plant tissues. Studies of fungal biodiversity lag far behind those of macro-organisms, such as plants. Estimates of global fungal richness are still widely debated. Utilizing previously collected specimens to study patterns of fungal diversity could significantly increase our understanding of overall patterns of biodiversity from snapshots in time. Here, we investigated the fungi inhabiting the phyllosphere of an endemic Hawaiian plant genus, Clermontia (Campanulaceae), throughout the main Hawaiian Islands. From just 20 DNA bank samples, using next generation DNA amplicon sequencing techniques, we uncovered approximately 2000 fungal operational taxonomic units (OTUs). Using these historic samples we tested the common ecological hypothesis of distance decay of community similarity through geographic space. We found a significant distance decay pattern with the Clermontia associated fungal communities across the Hawaiian Islands. This study also provides the first insights into elucidating patterns of microbial diversity through the use of DNA bank repository samples.