Cave Thiovulum (Candidatus Thiovulum stygium) differs metabolically and genomically from marine species - Université des Antilles Access content directly
Journal Articles The International Society of Microbiologial Ecology Journal Year : 2023

Cave Thiovulum (Candidatus Thiovulum stygium) differs metabolically and genomically from marine species

Mina Bizic
Traian Brad
Danny Ionescu
  • Function : Author
Lucian Barbu-Tudoran
Luca Zoccarato
  • Function : Author
Joost W Aerts
  • Function : Author
Jean-Marie Volland
Radu Popa
Jessica Ody
  • Function : Author
Daniel Vellone
  • Function : Author
Jean-François Flot
Scott Tighe
Serban M Sarbu
  • Function : Author

Abstract

Thiovulum spp. (Campylobacterota) are large sulfur bacteria that form veil-like structures in aquatic environments. The sulfidic Movile Cave (Romania), sealed from the atmosphere for ~5 million years, has several aqueous chambers, some with low atmospheric O 2 (~7%). The cave’s surface-water microbial community is dominated by bacteria we identified as Thiovulum . We show that this strain, and others from subsurface environments, are phylogenetically distinct from marine Thiovulum . We assembled a closed genome of the Movile strain and confirmed its metabolism using RNAseq. We compared the genome of this strain and one we assembled from public data from the sulfidic Frasassi caves to four marine genomes, including Candidatus Thiovulum karukerense and Ca . T. imperiosus, whose genomes we sequenced. Despite great spatial and temporal separation, the genomes of the Movile and Frasassi Thiovulum were highly similar, differing greatly from the very diverse marine strains. We concluded that cave Thiovulum represent a new species, named here Candidatus Thiovulum stygium. Based on their genomes, cave Thiovulum can switch between aerobic and anaerobic sulfide oxidation using O 2 and NO 3 - as electron acceptors, the latter likely via dissimilatory nitrate reduction to ammonia. Thus, Thiovulum is likely important to both S and N cycles in sulfidic caves. Electron microscopy analysis suggests that at least some of the short peritrichous structures typical of Thiovulum are type IV pili, for which genes were found in all strains. These pili may play a role in veil formation, by connecting adjacent cells, and in the motility of these exceptionally fast swimmers.Thiovulum spp. (Campylobacterota) are large sulfur bacteria that form veil-like structures in aquatic environments. The sulfidic Movile Cave (Romania), sealed from the atmosphere for ~5 million years, has several aqueous chambers, some with low atmospheric O 2 (~7%). The cave’s surface-water microbial community is dominated by bacteria we identified as Thiovulum . We show that this strain, and others from subsurface environments, are phylogenetically distinct from marine Thiovulum . We assembled a closed genome of the Movile strain and confirmed its metabolism using RNAseq. We compared the genome of this strain and one we assembled from public data from the sulfidic Frasassi caves to four marine genomes, including Candidatus Thiovulum karukerense and Ca . T. imperiosus, whose genomes we sequenced. Despite great spatial and temporal separation, the genomes of the Movile and Frasassi Thiovulum were highly similar, differing greatly from the very diverse marine strains. We concluded that cave Thiovulum represent a new species, named here Candidatus Thiovulum stygium. Based on their genomes, cave Thiovulum can switch between aerobic and anaerobic sulfide oxidation using O 2 and NO 3 - as electron acceptors, the latter likely via dissimilatory nitrate reduction to ammonia. Thus, Thiovulum is likely important to both S and N cycles in sulfidic caves. Electron microscopy analysis suggests that at least some of the short peritrichous structures typical of Thiovulum are type IV pili, for which genes were found in all strains. These pili may play a role in veil formation, by connecting adjacent cells, and in the motility of these exceptionally fast swimmers.

Dates and versions

hal-03998872 , version 1 (28-02-2023)

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Mina Bizic, Traian Brad, Danny Ionescu, Lucian Barbu-Tudoran, Luca Zoccarato, et al.. Cave Thiovulum (Candidatus Thiovulum stygium) differs metabolically and genomically from marine species. The International Society of Microbiologial Ecology Journal, 2023, 17 (3), pp.340-353. ⟨10.1038/s41396-022-01350-4⟩. ⟨hal-03998872⟩
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