Paradesulfovibrio onnuriensis gen. nov., sp. nov., a chemolithoautotrophic sulfate-reducing bacterium isolated from the Onnuri vent field of the Indian Ocean and reclassification of Desulfovibrio senegalensis as Paradesulfovibrio senegalensis comb. nov.

Abstract

An anaerobic, rod-shaped, mesophilic, chemolithoautotrophic, sulfate-reducing bacterial strain IOR2(T) was isolated from a newly found deep-sea hydrothermal vent (OVF, Onnuri Vent Field) area in the central Indian Ocean ridge (11 degrees 24 ' 88 '' S 66 degrees 25 ' 42 '' E, 2021 m water depth). The 16S rRNA gene sequence analysis revealed that the strain IOR2(T) was most closely related to Desulfovibrio senegalensis BLaC1(T) (96.7%). However, it showed low similarity with the members of the family Desulfovibrionaceae, such as Desulfovibrio tunisiensis RB22(T) (94.0%), D. brasiliensis LVform1(T) (93.9%), D. halophilus DSM 5663(T) (93.7%), and Pseudodesulfovibrio aespoeensis Aspo-2(T) (93.2%). The strain IOR2(T) could grow at 23-42 degrees C (optimum 37 degrees C), pH 5.0-8.0 (optimum pH 7.0) and with 0.5-6.5% (optimum 3.0%) NaCl. The strain could use lactate, pyruvate, H-2, and glycerol as electron donors and sulfate, thiosulfate, and sulfite as electron acceptors. The major fatty acids of the strain IOR2(T) were iso-C-15:0, iso-C-17:0, ante-iso-C-15:0, and summed feature 9 (C-16:0 methyl/iso-C-17:1 omega 9c). Both the strains IOR2(T) and BLaC1(T) could grow with CO2 and H-2 as the sole sources of carbon and energy, respectively. Genomic evidence for the Wood-Ljungdahl pathway in both the strains reflects chemolithoautotrophic growth. The DNA G + C content of the strain IOR2(T) and BLaC1(T) was 58.1-60.5 mol%. Based on the results of the phylogenetic and physiologic studies, Paradesulfovibrio onnuriensis gen. nov., sp. nov. with the type strain IOR2(T) (= KCTC 15845(T) = MCCC 1K04559(T)) was proposed to be a member of the family Desulfovibrionaceae. We have also proposed the reclassification of D. senegalensis as Paradesulfovibrio senegalensis comb. nov.