Functional diversity within the simple gut microbiota of the honey bee

Abstract

Animals living in social communities typically harbor a characteristic gut microbiota important for nutrition and pathogen defense. Accordingly, in the gut of the honey bee, Apis mellifera , a distinctive microbial community, composed of a taxonomically restricted set of species specific to social bees, has been identified. Despite the ecological and economical importance of honey bees and the increasing concern about population declines, the role of their gut symbionts for colony health and nutrition is unknown. Here, we sequenced the metagenome of the gut microbiota of honey bees. Unexpectedly, we found a remarkable degree of genetic diversity within the few bacterial species colonizing the bee gut. Comparative analysis of gene contents suggests that different species harbor distinct functional capabilities linked to host interaction, biofilm formation, and carbohydrate breakdown. Whereas the former two functions could be critical for pathogen defense and immunity, the latter one might assist nutrient utilization. In a γ-proteobacterial species, we identified genes encoding pectin-degrading enzymes likely involved in the breakdown of pollen walls. Experimental investigation showed that this activity is restricted to a subset of strains of this species providing evidence for niche specialization. Long-standing association of these gut symbionts with their hosts, favored by the eusocial lifestyle of honey bees, might have promoted the genetic and functional diversification of these bee-specific bacteria. Besides revealing insights into mutualistic functions governed by the microbiota of this important pollinator, our findings indicate that the honey bee can serve as a model for understanding more complex gut-associated microbial communities.

Swapping symbionts in spittlebugs: evolutionary replacement of a reduced genome symbiont

“…Ambiguously aligned regions and sites, including missing data, were removed from the multiple alignments before phylogenetic tree constructions. For the phylogeny of SLs (Supplementary Figure S5C), multiple alignments of six protein coding genes, alaS, ffh, pyrG, typA, uvrB and uvrC, were concatenated and subjected to a phylogenetic analysis (Engel et al, 2012). All phylogenetic trees were inferred with maximum likelihood method using RAxML v7.2.8 (Stamatakis, 2006).…”

Water fleas require microbiota for survival, growth and reproduction

“…The use of model organisms such as the fruit fly Drosophila melanogaster, the nematode Caenorhabditis elegans, the house mouse Mus musculus and the zebrafish Danio rerio has facilitated understanding of the mechanisms by which certain biological functions of the hosts are modulated by their microbiota (Rawls et al, 2004;Turnbaugh et al, 2006;Cabreiro and Gems 2013;Erkosar et al, 2013). As interest in environmental genomics emerges, the roles of microbiota in the ecology and evolution of an increasing number of non-model organisms are being investigated, revealing a high diversity in the types of effects observed (Fraune and Bosch, 2010;Engel et al, 2012;Koch and Schmid-Hempel, 2011;Brucker and Bordenstein, 2013). Here we present the first experiments addressing the role of microbiota in a crustacean model, Daphnia.…”

Ventosimonas gracilis gen. nov., sp. nov., a member of the Gammaproteobacteria isolated from Cephalotes varians ant guts representing a new family, Ventosimonadaceae fam. nov., within the order ‘Pseudomonadales’

“…Bacteria in this core microbiota consistently include members of the Burkholderiales, Rhizobiales, Xanthomonadales, Opitutales and Pseudomonadales phylotypes (Anderson et al, 2012;Hu et al, 2014;Russell et al, 2009), signifying their importance as stable, autochthonous members of the gut community (Hu et al, 2014;Sanders et al, 2014). These symbionts are likely to have coevolved with their hosts over their evolutionary history (Sanders et al, 2014), and, as shown for symbionts in the termite (Brune & Ohkuma, 2011;Wertz et al, 2012;Wertz & Breznak, 2007b) and honeybee gut (Engel et al, 2012;Engel & Moran, 2013;Kwong & Moran, 2013), likely confer beneficial functions to host nutrition and disease resistance (Dillon & Dillon, 2004).…”