EWU Digital Commons

PUB NCR

Bacterial symbionts are essential components of healthy biological systems and are increasingly identified as essential factors in the study and management of threatened species and ecosystems. Despite management shifts at the ecosystem level, microbial communities are often excluded from discussions of holobiont conservation in favor of the primary members of a symbiosis. In this study, we sought to fill the bacterial community knowledge gap for one of two federally endangered lichen species in the United States: Cetradonia linearis. We collected 28 samples of the endangered rock gnome lichen (Cetradonia linearis) from 15 sites to investigate the factors influencing microbiome composition and diversity within the thallus. DNA was extracted using a Powersoil Extraction kit and sequenced using 16S rRNA barcoding. Sequence processing and analyses of diversity were conducted in QIIME2. Core bacterial constituents of the microbiome were determined and visualized using the R package microbiome utilities. Proteobacteria (37.8 % ± 10.3) and Acidobacteria (25.9% ± 6.0) were the most abundant phyla recovered. Habitat, climate, and geography were all found to have significant influences on the bacterial community. A BLAST search of the nucleotide sequences of core members at a 90% threshold revealed shared amplicon sequence variants in the microbiomes of other lichens in the family Cladoniaceae. We concluded that the bacterial microbiome of Cetradonia linearis is influenced by environmental factors and that some bacterial taxa may be core to this group. Further exploration into the microbiomes of rare lichen species are needed to understand the importance of bacterial symbionts to lichen diversity and distribution.