Neobacillus rhizophilus sp. nov. and Neobacillus citreus sp. nov., isolated from the citrus rhizosphere soil

Two Gram-staining positive strains, FJAT-49825(T) and FJAT-50051(T) were isolated from a citrus rhizosphere soil sample. Strains FJAT-49825(T) and FJAT-50051(T) showed the highest 16S rRNA gene sequence similarity with the type strain of Neobacillus cucumis (98.4-98.5%). The 16S rRNA gene sequence similarity between strains FJAT-49825(T) and FJAT-50051(T) was 99.8%. Strain FJAT-49825(T) optimally grew at 35 degrees C, pH 6.0 in the absence of NaCl while strain FJAT-50051(T) grew at 40 degrees C, pH 7.0 and in presence of 2% NaCl (w/v). Both strains contained meso-2,6-diaminopimelic acid as the cell-wall diamino acid. The respiratory quinone of strains FJAT-49825(T) and FJAT-50051(T) was MK-7. The polar lipids of strain FJAT-49825(T) were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified aminolipid and unidentified lipid whereas strain FJAT-50051(T) polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid and unidentified lipid. The major fatty acids (> 10%) in both strains were iso-C-15:0 and anteiso-C-15:0. The genomic DNA G + C content of strains FJAT-49825(T) and FJAT-50051(T) were 40.8 and 41.1%, respectively. The average nucleotide identity and digital DNA-DNA hybridization value between strains FJAT-49825(T) and FJAT-50051(T) and with other members of the genus Neobacillus were lower than the cut-off value (95-96/70%) for interspecies identity. Based on the results, strains FJAT-49825(T) and FJAT-50051(T) represent two novel species of the genus Neobacillus, for which the names Neobacillus rhizophilus sp. nov. and Neobacillus citreus sp. nov. are proposed. The type strains are FJAT-49825(T) (= GDMCC 1.2592(T) = JCM 34834(T)) and FJAT-50051(T) (= GDMCC 1.2593(T) = JCM 34835(T)).