<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>Host-associated microbiomes have primarily been examined in the context of their internal microbial communities, but many animal species also contain microorganisms on external host surfaces that are important to host physiology. For nematodes, single strains of bacteria are known to adhere to the cuticle (e.g., <italic>Pasteuria penetrans</italic>), but the structure of a full external microbial community is uncertain. In prior research, we showed that internal gut microbiomes of nematodes (<italic>Plectus murrayi</italic>, <italic>Eudorylaimus antarcticus</italic>) and tardigrades from Antarctica’s McMurdo Dry Valleys were distinct from the surrounding environment and primarily driven by host identity. Building on this work, we extracted an additional set of individuals containing intact external microbiomes and amplified them for 16S and 18S rRNA metabarcoding. Our results showed that external bacterial microbiomes were more diverse than internal microbiomes, but less diverse than the surrounding environment. Host-specific bacterial compositional patterns were observed, and external microbiomes were most similar to their respective internal microbiomes. However, external microbiomes were more influenced by the environment than the internal microbiomes were. Non-host eukaryotic communities were similar in diversity to internal eukaryotic communities, but exhibited more stochastic patterns of assembly compared to bacterial communities, suggesting the lack of a structured external eukaryotic microbiome. Altogether, we provide evidence that nematode and tardigrade cuticles are inhabited by robust bacterial communities that are substantially influenced by the host, albeit less so than internal microbiomes are.</p></abstract>

Host-associated microbiomes have primarily been examined in the context of their internal microbial communities, but many animal species also contain microorganisms on external host surfaces that are important to host physiology. For nematodes, single strains of bacteria are known to adhere to the cuticle (e.g., Pasteuria penetrans), but the structure of a full external microbial community is uncertain. In prior research, we showed that internal gut microbiomes of nematodes (Plectus murrayi, Eudorylaimus antarcticus) and tardigrades from Antarctica’s McMurdo Dry Valleys were distinct from the surrounding environment and primarily driven by host identity. Building on this work, we extracted an additional set of individuals containing intact external microbiomes and amplified them for 16S and 18S rRNA metabarcoding. Our results showed that external bacterial microbiomes were more diverse than internal microbiomes, but less diverse than the surrounding environment. Host-specific bacterial compositional patterns were observed, and external microbiomes were most similar to their respective internal microbiomes. However, external microbiomes were more influenced by the environment than the internal microbiomes were. Non-host eukaryotic communities were similar in diversity to internal eukaryotic communities, but exhibited more stochastic patterns of assembly compared to bacterial communities, suggesting the lack of a structured external eukaryotic microbiome. Altogether, we provide evidence that nematode and tardigrade cuticles are inhabited by robust bacterial communities that are substantially influenced by the host, albeit less so than internal microbiomes are.

External and internal microbiomes of Antarctic nematodes are distinct, but more similar to each other than the surrounding environment

Journal of Nematology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Host-associated microbiomes have primarily been examined in the context of their internal microbial communities, but many animal species also contain...

External and internal microbiomes of Antarctic nematodes are distinct, but more similar to each other than the surrounding environment

Article Category: Research Paper

Published Online: Mar 09, 2023

Page range: -

Received: Aug 02, 2022

DOI: https://doi.org/10.2478/jofnem-2023-0004

Keywords
Antarctica, bacteria, community assembly, ecology, metabarcoding,

© 2023 McQueen et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

External and internal microbiomes of Antarctic nematodes are distinct, but more similar to each other than the surrounding environment

Article Category: Research Paper

Published Online: Mar 09, 2023

Page range: -

Received: Aug 02, 2022

DOI: https://doi.org/10.2478/jofnem-2023-0004

KeywordsAntarctica, bacteria, community assembly, ecology, metabarcoding,

© 2023 McQueen et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
Antarctica, bacteria, community assembly, ecology, metabarcoding,