A novel sulfate-reducing and nitrogen-fixing bacterium Fundidesulfovibrio soli sp. nov., isolated from paddy soils

A strictly anaerobic sulfate-reducing strain, designated SG60(T), was isolated from paddy soil collected in Fujian Province, China. Growth of strain SG60(T) was observed at 20-37 degrees C, pH 5.5-10.0 and 0-0.7% (w/v) NaCl. Strain SG60(T) showed the highest 16S rRNA sequence similarities to the type strains of Fundidesulfovibrio magnetotacticus FSS-1(T) (97.2%) and Fundidesulfovibrio putealis DSM 16056(T) (96.4%). Phylogenetic trees based on the16S rRNA sequence and genome-based phylogenomic tree constructed using 120 core genes showed that strain SG60(T) clustered with members of the genus Fundidesulfovibrio. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain SG60(T) and the most closely related type strain F. magnetotacticus were 78.2% and 21.6%, respectively. Strain SG60(T) contained MK-7 as the main respiratory quinone and anteiso-C-15:0, anteiso-C-17:1 omega 9c, iso-C-16:0 and iso-C-16:1 H as the major fatty acids. Strain SG60(T) produced desulfoviridin and possessed genes (nifHDK) encoding functions involved in nitrogen fixation. The genomic DNA G + C content was 65.5%. Based on the observed physiological properties, chemotaxonomic characteristics and ANI and dDDH values, strain SG60(T) represents a novel species of the genus Fundidesulfovibrio, for which the name Fundidesulfovibrio soli sp. nov. is proposed. The type strain is SG60(T) (= GDMCC 1.3310(T) = JCM 35676(T)).