Divergence together with microbes: A comparative study of the associated microbiomes in the closely related Littorina species

Abstract

Any multicellular organism during its life is involved in relatively stable interactions with microorganisms. The organism and its microbiome make up a holobiont, possessing a unique set of characteristics and evolving as a whole system. This study aimed to evaluate the degree of the conservativeness of microbiomes associated with intertidal gastropods. We studied the composition and the geographic and phylogenetic variability of the gut and body surface microbiomes of five closely related sympatric Littorina (Neritrema) spp. and a more distant species, L. littorea, from the sister subgenus Littorina (Littorina). Although snail-associated microbiomes included many lineages (207–603), they were dominated by a small number of OTUs of the genera Psychromonas, Vibrio, and Psychrilyobacter. The geographic variability was greater than the interspecific differences at the same collection site. While the microbiomes of the six Littorina spp. did not differ at the high taxonomic level, the OTU composition differed between groups of cryptic species and subgenera. A few species-specific OTUs were detected within the collection sites; notably, such OTUs never dominated microbiomes. We conclude that the composition of the high-rank taxa of the associated microbiome (“scaffolding enterotype”) is more evolutionarily conserved than the composition of the low-rank individual OTUs, which may be site- and / or species-specific.

First insights into the gut microbiomes and the diet of the Littorina snail ecotypes, a recently emerged marine evolutionary model

“…The present study was conducted at the local scale and there were no significant differences between sites that were only few km apart. There was a clear separation between the environmental microbiomes and the bacteria associated with the snail host, which agrees with the recent finding for the Pacific L. keenae (Neu et al, 2019) and several Atlantic Littorina species (Maltseva et al, 2021). Similar to the studies above we found some bacterial families exclusively associated with the snail host but the majorities of differences were at the abundance level.…”

“…There were some differences between the bacterial communities in the biofilm on the boulder beaches and lower and upper parts of the cliffs, in agreement with other studies on intertidal zonation of microbial communities (Arboleda-Baena et al, 2021;Weigel & Erwin, 2017). In the previous study we found regional differences in the intertidal microbiomes between Norway and Sweden (Maltseva et al, 2021). The present study was conducted at the local scale and there were no significant differences between sites that were only few km apart.…”

“…Most of our knowledge on the composition and the role of host‐associated microbiomes so far came from the mammals (Krajmalnik‐Brown et al, 2012 ; Ley et al, 2008 ) and insects (Douglas, 2014 ; Engel & Moran, 2013 ). Recently, the scope had expanded to other species, including marine mollusks (Choi et al, 2021 ; Fernandez‐Piquer et al, 2012 ; Gobet et al, 2018 ; Song et al, 2018 ), and among them the genus Littorina (Maltseva et al, 2021 ; Neu et al, 2019 ). These studies described host‐associated microbiomes, and also significant differences between closely related species of the snails (Maltseva et al, 2021 ).…”

“…Recently, the scope had expanded to other species, including marine mollusks (Choi et al, 2021 ; Fernandez‐Piquer et al, 2012 ; Gobet et al, 2018 ; Song et al, 2018 ), and among them the genus Littorina (Maltseva et al, 2021 ; Neu et al, 2019 ). These studies described host‐associated microbiomes, and also significant differences between closely related species of the snails (Maltseva et al, 2021 ). Further, a recent study discusses the possible role of microbes in the snail genome evolution (Maltseva et al, 2022 ).…”

Ecological filtering and phylogeographic structuring of Psychrilyobacter within two closely related limpet species from the Southern Ocean

“…Among invertebrates, mollusks stand out as ecologically significant and diverse phyla, being Gastropoda the richest class regarding species diversity (Neu et al 2019). Although descriptions of marine gastropod microbiota are accumulating, they mainly focus on commercial and/or northern hemisphere species, excluding most gastropod diversity (Neu et al 2019;Maltseva et al 2021b;Panova et al 2022). Moreover, the contribution of host diversification in shaping gastropod microbiota assembly remains largely unexplored.…”