The fungus Aphanoascella galapagosensis affects bacterial diversity of Galapagos giant tortoise carapaces.

This study focuses on characterizing the bacterial microbiome associated with the carapaces of three Galapagos giant tortoise species (Chelonoidis porteri, Chelonoidis donfaustoi, and Chelonoidis vandenburghi) and assessing the impact of whitish lesions caused by the fungus Aphanoascella galapagosensis. Using Oxford Nanopore sequencing and taxonomic analysis, the researchers identified a core set of bacterial genera common to all tortoise carapaces, while finding significant differences in bacterial community composition and diversity between carapaces with and without fungal lesions. The presence of A. galapagosensis was associated with increased bacterial richness and distinct microbial profiles, suggesting fungal influence on the carapace microbiome. These findings provide a baseline for understanding the ecological interactions among bacteria, fungi, and tortoise hosts, which may be important for monitoring the health and conservation of these threatened species.