It is well known now, that microorganisms, associated with metazoans, can influence adaptive scope of their hosts. This poses an important question about the fate of associated microbiome during ecology-driven speciation. In this way, the characterization of microbiomes associated with recently diverged species, demonstrating ecological shift, may help to clarify this point. When associated microbiome is described, temporal and spatial variability should be taken into account. In our study, we analysed microbiomes associated with sister-species Littorina fabalis and L. obtusata collected from two remote regions (Barents Sea and White Sea); in the latter region, the samples were obtained in the summer and autumn seasons.
The gut samples were obtained individually, samples of the mantle (pooled ones) and of environmental biofilms, taken from living (fucoids) and non-living (stones) substrates, were also used in the analysis. Bacterial composition was analyzed using 16S-rDNA metabarcoding, followed by the ASV identification in the SILVA database. Several principal conclusions can be done. [1] The environmental and body-surface microbiomes significantly differ from the gut microbiomes. Species richness and community evenness in the environmental samples were higher than in the gut-associated ones. [2] There were weak but significant differences between the gut-associated microbiota of the two species in the analysis. Interestingly, the number of bacterial lineages typically associated with L. obtusata was significantly higher than of those specific for L. fabalis. [3] Seasonal variability of the gut-associated microbiota was strong in both analysed species. In the autumn, the snail-associated bacterial communities significantly decreased in lineages richness; moreover, between-species differences in the microbiome composition were insignificant in this season. Possible interpretations of these phenomena will be presented in my talk.
The project is supported by the Russian Science Foundation 19-14-00321, PI A.I.Granovitch