Two novel diazotrophic Paenibacillaceae bacteria, Gorillibacterium terrae sp. nov. and Oryzibacillus soli gen. nov., sp. nov., isolated from rice fields

Two novel aerobic, Gram-stain-positive, endospore-forming and short rod-shaped bacterial strains, designated as sgz500922 T and sgz5001074 T , were isolated from paddy soils in Fujian, PR China. The taxonomic position of two strains was determined using polyphasic taxonomy and phylogenomic analysis. Phylogenetic analysis and 16S rRNA gene sequence comparisons revealed that strains sgz500922 T and sgz5001074 T formed a distinct clade with Gorillibacterium massiliense G5 T and shared sequence similarities of 96.3 and 93.5%, respectively. The average nucleotide identity value between the two strains and their closest reference strain was 73.1 and 72.3%, below the species threshold value of 95.0–96.0%, while the average amino acid identity values between sgz5001074 T and G. massiliense and Paenibacillus contaminans were 62.4 and 63.2%, respectively. Optimal growth conditions of strains sgz500922 T and sgz5001074 T were pH 7.0 and 30 °C on Reasoner’s 2A agar. Major fatty acids of sgz500922 T and sgz5001074 T were anteiso-C 15:0 and C 16:0 . The main polar lipids included diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Both strains contained nitrogenase core gene nifHDK in their genomes, and nitrogenase and total nitrogen accumulation estimated their nitrogen-fixing ability. According to the phenotypic, genotypic and phylogenetic data, strains sgz500922 T and sgz5001074 T represent two novel species of the family Paenibacillaceae , for which the names Gorillibacterium terrae sp. nov. and Oryzibacillus soli gen. nov., sp. nov., respectively, were proposed (sgz500922 T =MCCC 1K09374 T =KCTC 43730 T , sgz5001074 T (=MCCC 1K09398 T =KCTC 43742 T ).