Genomic Characterization and Environmental Distribution of a Thermophilic Anaerobe Dissulfurirhabdus thermomarina SH388T Involved in Disproportionation of Sulfur Compounds in Shallow Sea Hydrothermal Vents

Maxime Allioux,Karine Alain,Zongze Shao,Galina Slobodkina,Alexander Slobodkin,Stéven Yvenou,Mohamed Jebbar

doi:10.3390/microorganisms8081132

Abstract

Marine hydrothermal systems are characterized by a pronounced biogeochemical sulfur cycle with the participation of sulfur-oxidizing, sulfate-reducing and sulfur-disproportionating microorganisms. The diversity and metabolism of sulfur disproportionators are studied to a much lesser extent compared with other microbial groups. Dissulfurirhabdus thermomarina SH388T is an anaerobic thermophilic bacterium isolated from a shallow sea hydrothermal vent. D. thermomarina is an obligate chemolithoautotroph able to grow by the disproportionation of sulfite and elemental sulfur. Here, we present the results of the sequencing and analysis of the high-quality draft genome of strain SH388T. The genome consists of a one circular chromosome of 2,461,642 base pairs, has a G + C content of 71.1 mol% and 2267 protein-coding sequences. The genome analysis revealed a complete set of genes essential to CO2 fixation via the reductive acetyl-CoA (Wood-Ljungdahl) pathway and gluconeogenesis. The genome of D. thermomarina encodes a complete set of genes necessary for the dissimilatory reduction of sulfates, which are probably involved in the disproportionation of sulfur. Data on the occurrences of Dissulfurirhabdus 16S rRNA gene sequences in gene libraries and metagenome datasets showed the worldwide distribution of the members of this genus. This study expands our knowledge of the microbial contribution into carbon and sulfur cycles in the marine hydrothermal environments.

Highlights

Anaerobic microorganisms are involved in biogeochemical cycles and are vital for global ecosystem maintenance, including marine hydrothermal vents
The bacteria Thermosulfuriphilus ammonigenes, Dissulfuribacter thermophilus and Thermosulfurimonas dismutans were isolated from deep-sea hydrothermal vents [4,5,6], and the species Thermosulfurimonas marina and Dissulfurirhabdus thermomarina from shallow hydrothermal systems [7,8]
The complete genome sequence of Dissulfurirhabdus thermomarina strain SH388T was deposited in GenBank databases under the accession number JAATWC000000000

Summary

Introduction

Anaerobic microorganisms are involved in biogeochemical cycles and are vital for global ecosystem maintenance, including marine hydrothermal vents. Like deep-sea hydrothermal vents, are areas characterized by the discharge of hot, anoxic, mineral-loaded, and reduced compound-rich fluid into the cold and oxygenated water of the ocean floor [1,2]. Sulfur is a ubiquitous element in the hydrothermal environment and is very important for energy production. It is found in various oxidation states in the mineral structures forming chimneys, in the fluid emitted from the chimneys, especially as hydrogen sulfide (H2S) and in the surrounding sea-water as sulfate. The bacteria Thermosulfuriphilus ammonigenes, Dissulfuribacter thermophilus and Thermosulfurimonas dismutans were isolated from deep-sea hydrothermal vents [4,5,6], and the species Thermosulfurimonas marina and Dissulfurirhabdus thermomarina from shallow hydrothermal systems [7,8]

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Conclusion