Microbiome divergence of marine gastropod species separated by the Isthmus of Panama

Abstract

The rise of the Isthmus of Panama ~3.5 mya separated populations of many marine organisms, which then diverged into new geminate sister species currently living in the Eastern Pacific Ocean and Caribbean Sea. However, we know very little about how such evolutionary divergences of host species have shaped their microbiomes. Here, we compared the microbiomes of whole-body and shell-surface samples of geminate species of marine gastropods in the genera Cerithium and Cerithideopsis to those of congeneric outgroups. Our results show that the effects of the Isthmus on microbiome composition varied among host genera and between sample types within the same hosts. In the whole-body samples, microbiome compositions of geminate species pairs in the focal genera tended to be similar, likely due to host filtering, although the strength of this relationship varied among the two groups and across similarity metrics. Shell-surface communities showed contrasting patterns, with co-divergence between the host taxa and a small number of microbial clades evident in Cerithideopsis, but not Cerithium. These results suggest that (i) the rise of the Isthmus of Panama affected microbiomes of geminate hosts in a complex and clade-specific manner and (ii) host-associated microbial taxa respond differently to vicariance events than the hosts themselves.

Prokaryotic communities of the French Polynesian sponge Dactylospongia metachromia display a site-specific and stable diversity during an aquaculture trial

“…Such results, returning rather small globally-distributed taxa, are similar to previous works focusing on core communities de ned from multiple species coming from very distinct locations(Schmitt et al 2012a, b).The core taxa of D. metachromia within the phylum Acidobacteriota, were assigned to Vicinamibacterale, Thermoanaerobaculales and the uncultured group PAUC26f. Marine are not strictly sponge-related, as they have also been extracted from molluscs(Neu et al 2021b;Banker et al 2022). Likewise, a core ASV was a liated to the class bacteriap25 (Myxococcales; Proteobacteria), which is found in soils and terrestrial plants such as some non-indigenous Asteraceae that have been introduced in French Polynesia(Landwehr et al 2016; Monteiro 2020).One of the main core ASVs belongs to the candidate phylum PAUC34f, which is described as part of the most important clades directly associated with the cycling of dissolved organic matter (DOM) within the Caribbean sponge Plakortis angulospiculatus(Campana et al 2021a).…”