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

A strictly anaerobic sulfate-reducing strain, designated SG60, was isolated from paddy soil collected in Fujian Province, China. Growth of strain SG60 was observed at 20-37 °C, pH 5.5-10.0 and 0-0.7% (w/v) NaCl. Strain SG60 showed the highest 16S rRNA sequence similarities to the type strains of Fundidesulfovibrio magnetotacticus FSS-1 (97.2%) and Fundidesulfovibrio putealis DSM 16056 (96.4%). Phylogenetic trees based on the16S rRNA sequence and genome-based phylogenomic tree constructed using 120 core genes showed that strain SG60 clustered with members of the genus Fundidesulfovibrio. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain SG60 and the most closely related type strain F. magnetotacticus were 78.2% and 21.6%, respectively. Strain SG60 contained MK-7 as the main respiratory quinone and anteiso-C, anteiso-C ω9c, iso-C and iso-C H as the major fatty acids. Strain SG60 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 represents a novel species of the genus Fundidesulfovibrio, for which the name Fundidesulfovibrio soli sp. nov. is proposed. The type strain is SG60 (= GDMCC 1.3310 = JCM 35676).