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The microbiome of a bacterivorous marine choanoflagellate contains a resource-demanding obligate bacterial associate.

ABSTRACT: Microbial predators such as choanoflagellates are key players in ocean food webs. Choanoflagellates, which are the closest unicellular relatives of animals, consume bacteria and also exhibit marked biological transitions triggered by bacterial compounds, yet their native microbiomes remain uncharacterized. Here we report the discovery of a ubiquitous, uncultured bacterial lineage we name Candidatus Comchoanobacterales ord. nov., related to the human pathogen Coxiella and physically associated with the uncultured marine choanoflagellate Bicosta minor. We analyse complete 'Comchoano' genomes acquired after sorting single Bicosta cells, finding signatures of obligate host-dependence, including reduction of pathways encoding glycolysis, membrane components, amino acids and B-vitamins. Comchoano encode the necessary apparatus to import energy and other compounds from the host, proteins for host-cell associations and a type IV secretion system closest to Coxiella's that is expressed in Pacific Ocean metatranscriptomes. Interactions between choanoflagellates and their microbiota could reshape the direction of energy and resource flow attributed to microbial predators, adding complexity and nuance to marine food webs.

SUBMITTER: Needham DM

PROVIDER: S-EPMC9418006 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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The microbiome of a bacterivorous marine choanoflagellate contains a resource-demanding obligate bacterial associate.

Needham David M DM Poirier Camille C Bachy Charles C George Emma E EE Wilken Susanne S Yung Charmaine C M CCM Limardo Alexander J AJ Morando Michael M Sudek Lisa L Malmstrom Rex R RR Keeling Patrick J PJ Santoro Alyson E AE Worden Alexandra Z AZ

Nature microbiology 20220815 9

Microbial predators such as choanoflagellates are key players in ocean food webs. Choanoflagellates, which are the closest unicellular relatives of animals, consume bacteria and also exhibit marked biological transitions triggered by bacterial compounds, yet their native microbiomes remain uncharacterized. Here we report the discovery of a ubiquitous, uncultured bacterial lineage we name Candidatus Comchoanobacterales ord. nov., related to the human pathogen Coxiella and physically associated wi ...[more]

PMID: 35970961

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The microbiome of a bacterivorous marine choanoflagellate contains a resource-demanding obligate bacterial associate.

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The microbiome of a bacterivorous marine choanoflagellate contains a resource-demanding obligate bacterial associate.

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