Abstract
Freshwater mussels are both among the most diverse and endangered faunas worldwide. The gut microbiota of species plays a key role in nutrition and immunity, such as preventing it from pathogen invasion, synthesizing beneficial secondary metabolites, and contributing to the digestion of complex nutrients. Information on the gut microbiota could have significant implications for conservation biology, especially for threatened or endangered species. However, there is relatively little study into the gut microbiota of freshwater mussels. Here, the gut microbiota diversity was analyzed in endangered (Solenaia carinata), economical (Sinohyriopsis cumingii), and common (Sinanodonta woodiana) freshwater mussels using 16S rRNA gene sequencing. This study represents the first to compare the gut microbiota diversity of endangered, economical, and common Chinese freshwater mussels. The results showed that 13,535 OTUs were found in S. carinata, 12,985 OTUs in S. cumingii, and 9,365 OTUs in S. woodiana. The dominant phylum in S. carinata and S. cumingii was Fusobacteria, and was Firmicutes in S. woodiana. Alpha diversity indices indicated that S. carinata and S. cumingii had a higher abundance and diversity of gut microbiota than S. woodiana. The composition of gut microbiota was different among three freshwater mussels, but their composition variation was not significant. This study provides insight for the conservation of freshwater mussel biodiversity, which will not only help conserve these vulnerable groups but also, will offer wider benefits to freshwater ecosystems.