COMPOSIZIONE E VARIABILITÁ DEI MICROBIOMI ASSOCIATI CON L’ANFIPODE TALITRUS SALTATOR (MONTAGU) (CRUSTACEA, AMPHIPODA)

Talitrus saltator is one of the key species of the damp band of European sandy beaches. Despite the large interest on animal-associated bacteria and on their relationships with animal host’s ecology and metabolism, only a few and preliminary data are present concerning the bacterial communities (microbiomes) associated with T. saltator. Here we characterized the microbiome present in 30 individuals of T. saltator belonging to seven populations distributed along the Tuscan coast (Italy) by using Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of amplified 16S rRNA genes. Results showed a high diversity of the microbiome, composed mainly by members of Alphaproteobacteria, Gammaproteobacteria, Bacillales and Clostridiales classes. Interestingly, the microbiome fingerprints were highly variable among individuals, even from the same populations, the inter-individual differences accounting for 88.7% of total fingerprints variance. However, statistically significant population-specific microbiome signatures were detected, and accounted for the remaining 11.3% of total fingerprints variance. These population-specific differences were mainly attributed to sequences from members of known host-associated bacteria such as Gammaproteobacteria and Betaproteobacteria, Cytophagia and Spirochaetia. In conclusion this study sheds light on the microbiome associated with an amphipod species and on the inter-individual microbiome variation with potential importance for understanding amphipod trophic and ecologic processes.