Bacterial community composition and diversity in an ancestral ant fungus symbiosis

Abstract

Fungus-farming ants (Hymenoptera: Formicidae, Attini) exhibit some of the most complex microbial symbioses because both macroscopic partners (ants and fungus) are associated with a rich community of microorganisms. The ant and fungal microbiomes are thought to serve important beneficial nutritional and defensive roles in these symbioses. While most recent research has investigated the bacterial communities in the higher attines (e.g. the leaf-cutter ant genera Atta and Acromyrmex), which are often associated with antibiotic-producing Actinobacteria, very little is known about the microbial communities in basal lineages, labeled as 'lower attines', which retain the ancestral traits of smaller and more simple societies. In this study, we used 16S amplicon pyrosequencing to characterize bacterial communities of the lower attine ant Mycocepurus smithii among seven sampling sites in central Panama. We discovered that ant and fungus garden-associated microbiota were distinct from surrounding soil, but unlike the situation in the derived fungus-gardening ants, which show distinct ant and fungal microbiomes, microbial community structure of the ants and their fungi were similar. Another surprising finding was that the abundance of actinomycete bacteria was low and instead, these symbioses were characterized by an abundance of Lactobacillus and Pantoea bacteria. Furthermore, our data indicate that Lactobacillus strains are acquired from the environment rather than acquired vertically.

Host identity and symbiotic association affects the taxonomic and functional diversity of the clownfish-hosting sea anemone microbiome

“…[11,39]) and microbiome convergence has also been noted in some, but not all, leaf-cutter ant symbioses (e.g. [40,41]). Pratte et al [31] recently demonstrated changes in microbiome composition between anemone-hosting and non-hosting A. clarkii clownfish in a laboratory setting, implying either direct microbial transfer from anemone to clownfish or a shift in microbial diversity in response to the interaction.…”

The evolution of abdominal microbiomes in fungus‐growing ants

“…Members of γ-Proteobacteria were found in the attine ant abdomens but only in traces and then primarily in the rectum (Figure 2). This finding is of interest because representatives of γ-Proteobacteria have repeatedly been reported as being abundant in the fungus gardens of attine ants (Aylward et al, 2014(Aylward et al, , 2012Kellner, Ishak, Linksvayer, & Mueller, 2015;Pinto-Tomás et al, 2009), although it remains unclear whether these were the same OTUs or not. These previously reported γ-Proteobacteria are mostly Enterobacteriaceae with abilities to fix nitrogen in laboratory fungus gardens of Atta leaf-cutting ants (Pinto-Tomás et al, 2009).…”

Bacterial microbiomes from vertically transmitted fungal inocula of the leaf‐cutting ant Atta texana

“…Several studies used next-generation sequencing approaches to characterize microbiomes from fungus gardens of leafcutter ants (Suen et al, 2010;Aylward et al, 2012;Aylward et al, 2014) and non-leafcutter attine species (Sen et al, 2009;Ishak et al, 2011;Liberti et al, 2015;Kellner et al, 2015). These studies documented the presence of a great bacterial diversity in attine gardens (e.g., Enterobacter, Pseudomonas, Klebsiella, Pantoea and others), and Aylward et al (2012) investigated the potential functions of bacteria in Atta gardens using meta-proteomic analyses.…”