More Like this

1. Evaluating de Novo Assembly and Binning Strategies for Time Series Drinking Water Metagenomes

   https://doi.org/10.1128/Spectrum.01434-21  

   Vosloo, Solize ; Huo, Linxuan ; Anderson, Christopher L. ; Dai, Zihan ; Sevillano, Maria ; Pinto, Ameet ( December 2021 , Microbiology Spectrum)

   Gralnick, Jeffrey A. (Ed.)

   ABSTRACT Reconstructing microbial genomes from metagenomic short-read data can be challenging due to the unknown and uneven complexity of microbial communities. This complexity encompasses highly diverse populations, which often includes strain variants. Reconstructing high-quality genomes is a crucial part of the metagenomic workflow, as subsequent ecological and metabolic inferences depend on their accuracy, quality, and completeness. In contrast to microbial communities in other ecosystems, there has been no systematic assessment of genome-centric metagenomic workflows for drinking water microbiomes. In this study, we assessed the performance of a combination of assembly and binning strategies for time series drinking water metagenomes that were collected over 6 months. The goal of this study was to identify the combination of assembly and binning approaches that result in high-quality and -quantity metagenome-assembled genomes (MAGs), representing most of the sequenced metagenome. Our findings suggest that the metaSPAdes coassembly strategies had the best performance, as they resulted in larger and less fragmented assemblies, with at least 85% of the sequence data mapping to contigs greater than 1 kbp. Furthermore, a combination of metaSPAdes coassembly strategies and MetaBAT2 produced the highest number of medium-quality MAGs while capturing at least 70% of the metagenomes based on read recruitment. Utilizing different assembly/binning approaches also assists in the reconstruction of unique MAGs from closely related species that would have otherwise collapsed into a single MAG using a single workflow. Overall, our study suggests that leveraging multiple binning approaches with different metaSPAdes coassembly strategies may be required to maximize the recovery of good-quality MAGs. IMPORTANCE Drinking water contains phylogenetic diverse groups of bacteria, archaea, and eukarya that affect the esthetic quality of water, water infrastructure, and public health. Taxonomic, metabolic, and ecological inferences of the drinking water microbiome depend on the accuracy, quality, and completeness of genomes that are reconstructed through the application of genome-resolved metagenomics. Using time series metagenomic data, we present reproducible genome-centric metagenomic workflows that result in high-quality and -quantity genomes, which more accurately signifies the sequenced drinking water microbiome. These genome-centric metagenomic workflows will allow for improved taxonomic and functional potential analysis that offers enhanced insights into the stability and dynamics of drinking water microbial communities. 

   more » « less
2. Are you what you eat? A highly transient and prey‐influenced gut microbiome in the grey house spider Badumna longinqua

   https://doi.org/10.1111/mec.15370  

   Kennedy, Susan R. ; Tsau, Sophia ; Gillespie, Rosemary ; Krehenwinkel, Henrik ( February 2020 , Molecular Ecology)

   Stable core microbial communities have been described in numerous animal species and are commonly associated with fitness benefits for their hosts. Recent research, however, highlights examples of species whose microbiota are transient and environmentally derived. Here, we test the effect of diet on gut microbial community assembly in the spiderBadumna longinqua. Using 16S rRNA gene amplicon sequencing combined with quantitative PCR, we analyzed diversity and abundance of the spider's gut microbes, and simultaneously characterized its prey communities using nuclear rRNA markers. We found a clear correlation between community similarity of the spider's insect prey and gut microbial DNA, suggesting that microbiome assembly is primarily diet‐driven. This assumption is supported by a feeding experiment, in which two types of prey—crickets and fruit flies—both substantially altered microbial diversity and community similarity between spiders, but did so in different ways. After cricket consumption, numerous cricket‐derived microbes appeared in the spider's gut, resulting in a rapid homogenization of microbial communities among spiders. In contrast, few prey‐associated bacteria were detected after consumption of fruit flies; instead, the microbial community was remodelled by environmentally sourced microbes, or abundance shifts of rare taxa in the spider's gut. The reshaping of the microbiota by both prey taxa mimicked a stable core microbiome in the spiders for several weeks post feeding. Our results suggest that the spider's gut microbiome undergoes pronounced temporal fluctuations, that its assembly is dictated by the consumed prey, and that different prey taxa may remodel the microbiota in drastically different ways.

    

   more » « less
3. Conserved microbiota among young Heliconius butterfly species

   https://doi.org/10.7717/peerj.5502  

   van Schooten, Bas ; Godoy-Vitorino, Filipa ; McMillan, W. Owen ; Papa, Riccardo ( January 2018 , PeerJ)

   Background Insects are the most diverse group of animals which have established intricate evolutionary interactions with bacteria. However, the importance of these interactions is still poorly understood. Few studies have focused on a closely related group of insect species, to test the similarities and differences between their microbiota. Heliconius butterflies are a charismatic recent insect radiation that evolved the unique ability to use pollen as a protein source, which affected life history traits and resulted in an elevated speciation rates. We hypothesize that different Heliconius butterflies sharing a similar trophic pollen niche, harbor a similar gut flora within species, population and sexes. Methods To test our hypothesis, we characterized the microbiota of 38 adult male and female butterflies representing six species of Heliconius butterflies and 2 populations of the same species. We sequenced the V4 region of the 16S rRNA gene with the Roche 454 system and analyzed the data with standard tools for microbiome analysis. Results Overall, we found a low microbial diversity with only 10 OTUs dominating across all individuals, mostly Proteobacteria and Firmicutes, which accounted for  99.5% of the bacterial reads. When rare reads were considered, we identified a total of 406 OTUs across our samples. We identified reads within Phyla Chlamydiae , found in 5 butterflies of four species. Interestingly, only three OTUs were shared among all 38 individuals ( Bacillus, Enterococcus and Enterobacteriaceae ). Altogether, the high individual variation overshadowed species and sex differences. Thus, bacterial communities were not structured randomly with 13% of beta-diversity explained by species, and 40 rare OTUs being significantly different across species. Finally, 13 OTUs, including the intercellular symbiont Spiroplasma, varied significantly in relative abundance between males and females. Discussion The Heliconius microbial communities in these 38 individuals show a low diversity with few differences in the rare microbes between females, males, species or populations. Indeed, Heliconius butterflies, similarly to other insects, are dominated by few OTUs, mainly from Proteobacteria and Firmicutes. The overall low microbial diversity observed contrasts with the high intra-species variation in microbiome composition. This could indicate that much of the microbiome maybe acquired from their surroundings. The significant differences between species and sexes were restricted to rare taxa, which could be important for microbial community stability under changing conditions as seen in other host-microbiome systems. The presence of symbionts like Spiroplasma or Chlamydiae , identified in this study for the first time in Heliconius , could play a vital role in their behavior and evolution by vertical transmission. Altogether, our study represents a step forward into the description of the microbial diversity in a charismatic group of closely related butterflies. 

   more » « less
4. Home-field advantage affects the local adaptive interaction between Andropogon gerardii ecotypes and root-associated bacterial communities

   https://doi.org/10.1128/spectrum.00208-23  

   Kazarina, Anna ; Sarkar, Soumyadev ; Thapa, Shiva ; Heeren, Leah ; Kamke, Abgail ; Ward, Kaitlyn ; Hartung, Eli ; Ran, Qinghong ; Galliart, Matthew ; Jumpponen, Ari ; et al ( October 2023 , Microbiology Spectrum)

   Arias, Renee S. (Ed.)

   Due to climate change, drought frequencies and severities are predicted to increase across the United States. Plant responses and adaptation to stresses depend on plant genetic and environmental factors. Understanding the effect of those factors on plant performance is required to predict species’ responses to environmental change. We used reciprocal gardens planted with distinct regional ecotypes of the perennial grassAndropogon gerardiiadapted to dry, mesic, and wet environments to characterize their rhizosphere communities using 16S rRNA metabarcode sequencing. Even though the local microbial pool was the main driver of these rhizosphere communities, the significant plant ecotypic effect highlighted active microbial recruitment in the rhizosphere, driven by ecotype or plant genetic background. Our data also suggest that ecotypes planted at their homesites were more successful in recruiting rhizosphere community members that were unique to the location. The link between the plants’ homesite and the specific local microbes supported the “home field advantage” hypothesis. The unique homesite microbes may represent microbial specialists that are linked to plant stress responses. Furthermore, our data support ecotypic variation in the recruitment of congeneric but distinct bacterial variants, highlighting the nuanced plant ecotype effects on rhizosphere microbiome recruitment. These results improve our understanding of the complex plant host–soil microbe interactions and should facilitate further studies focused on exploring the functional potential of recruited microbes. Our study has the potential to aid in predicting grassland ecosystem responses to climate change and impact restoration management practices to promote grassland sustainability.

   In this study, we used reciprocal gardens located across a steep precipitation gradient to characterize rhizosphere communities of distinct dry, mesic, and wet regional ecotypes of the perennial grassAndropogon gerardii. We used 16S rRNA amplicon sequencing and focused oligotyping analysis and showed that even though location was the main driver of the microbial communities, ecotypes could potentially recruit distinct bacterial populations. We showed that differentA. gerardiiecotypes were more successful in overall community recruitment and recruitment of microbes unique to the “home” environment, when growing at their “home site.” We found evidence for “home-field advantage” interactions between the host and host–root-associated bacterial communities, and the capability of ecotypes to recruit specialized microbes that were potentially linked to plant stress responses. Our study aids in a better understanding of the factors that affect plant adaptation, improve management strategies, and predict grassland function under the changing climate.

    

   more » « less
5. Large Comparative Analyses of Primate Body Site Microbiomes Indicate that the Oral Microbiome Is Unique among All Body Sites and Conserved among Nonhuman Primates

   https://doi.org/10.1128/spectrum.01643-21  

   Asangba, Abigail E. ; Mugisha, Lawrence ; Rukundo, Joshua ; Lewis, Rebecca J. ; Halajian, Ali ; Cortés-Ortiz, Liliana ; Junge, Randall E. ; Irwin, Mitchell T. ; Karlson, Johan ; Perkin, Andrew ; et al ( June 2022 , Microbiology Spectrum)

   Kormas, Konstantinos Aristomenis (Ed.)

   ABSTRACT The study of the mammalian microbiome serves as a critical tool for understanding host-microbial diversity and coevolution and the impact of bacterial communities on host health. While studies of specific microbial systems (e.g., in the human gut) have rapidly increased, large knowledge gaps remain, hindering our understanding of the determinants and levels of variation in microbiomes across multiple body sites and host species. Here, we compare microbiome community compositions from eight distinct body sites among 17 phylogenetically diverse species of nonhuman primates (NHPs), representing the largest comparative study of microbial diversity across primate host species and body sites. Analysis of 898 samples predominantly acquired in the wild demonstrated that oral microbiomes were unique in their clustering, with distinctive divergence from all other body site microbiomes. In contrast, all other body site microbiomes clustered principally by host species and differentiated by body site within host species. These results highlight two key findings: (i) the oral microbiome is unique compared to all other body site microbiomes and conserved among diverse nonhuman primates, despite their considerable dietary and phylogenetic differences, and (ii) assessments of the determinants of host-microbial diversity are relative to the level of the comparison (i.e., intra-/inter-body site, -host species, and -individual), emphasizing the need for broader comparative microbial analyses across diverse hosts to further elucidate host-microbial dynamics, evolutionary and biological patterns of variation, and implications for human-microbial coevolution. IMPORTANCE The microbiome is critical to host health and disease, but much remains unknown about the determinants, levels, and evolution of host-microbial diversity. The relationship between hosts and their associated microbes is complex. Most studies to date have focused on the gut microbiome; however, large gaps remain in our understanding of host-microbial diversity, coevolution, and levels of variation in microbiomes across multiple body sites and host species. To better understand the patterns of variation and evolutionary context of host-microbial communities, we conducted one of the largest comparative studies to date, which indicated that the oral microbiome was distinct from the microbiomes of all other body sites and convergent across host species, suggesting conserved niche specialization within the Primates order. We also show the importance of host species differences in shaping the microbiome within specific body sites. This large, comparative study contributes valuable information on key patterns of variation among hosts and body sites, with implications for understanding host-microbial dynamics and human-microbial coevolution. 

   more » « less