Three Fe(III)-reducing and nitrogen-fixing bacteria, Anaeromyxobacter terrae sp. nov., Anaeromyxobacter oryzisoli sp. nov. and Anaeromyxobacter soli sp. nov., isolated from paddy soil

Three microaerophilic bacterial strains, designated SG22 T , SG63 T and SG29 T were isolated from paddy soils in PR China. Cells of these strains were Gram-staining-negative and long rod-shaped. SG22 T , SG63 T and SG29 T showed the highest 16S rRNA gene sequence similarities with the members of the genus Anaeromyxobacter . The results of phylogenetic and phylogenomic analysis also indicated that these strains clustered with members of the genus Anaeromyxobacter . The main respiratory menaquinone of SG22 T , SG63 T and SG29 T was MK-8 and the major fatty acids were iso-C 15 : 0 , iso-C 17 : 0 and C 16 : 0 . SG22 T , SG29 T and SG63 T not only possessed iron reduction ability but also harboured genes ( nifHDK ) encoding nitrogenase. The genomic DNA G+C contents of SG22 T , SG63 T and SG29 T ranged from 73.3 to 73.5 %. The average nucleotide identity (ANI) and digital DNA–DNA hybridisation (dDDH) values between SG22 T , SG63 T and SG29 T and the closely related species of the genus Anaeromyxobacter were lower than the cut-off values (dDDH 70 % and ANI 95–96 %) for prokaryotic species delineation. On the basis of these results, strains SG22 T , SG63 T and SG29 T represent three novel species within the genus Anaeromyxobacter , for which the names Anaeromyxobacter terrae sp. nov., Anaeromyxobacter oryzisoli sp. nov. and Anaeromyxobacter soli sp. nov., are proposed. The type strains are SG22 T (= GDMCC 1.3185 T = JCM 35581 T ), SG63 T (= GDMCC 1.2914 T = JCM 35124 T ) and SG29 T (= GDMCC 1.2911 T = JCM 35123 T ).