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

Arch Microbiol. 2022 Apr 25;204(5):281. doi: 10.1007/s00203-022-02886-x.

Abstract

Two Gram-staining positive strains, FJAT-49825T and FJAT-50051T were isolated from a citrus rhizosphere soil sample. Strains FJAT-49825T and FJAT-50051T 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-49825T and FJAT-50051T was 99.8%. Strain FJAT-49825T optimally grew at 35 °C, pH 6.0 in the absence of NaCl while strain FJAT-50051T grew at 40 °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-49825T and FJAT-50051T was MK-7. The polar lipids of strain FJAT-49825T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified aminolipid and unidentified lipid whereas strain FJAT-50051T polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid and unidentified lipid. The major fatty acids (> 10%) in both strains were iso-C15:0 and anteiso-C15:0. The genomic DNA G + C content of strains FJAT-49825T and FJAT-50051T were 40.8 and 41.1%, respectively. The average nucleotide identity and digital DNA-DNA hybridization value between strains FJAT-49825T and FJAT-50051T 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-49825T and FJAT-50051T 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-49825T (= GDMCC 1.2592T = JCM 34834T) and FJAT-50051T (= GDMCC 1.2593T = JCM 34835T).

Keywords: Citrus rhizosphere; Neobacillus citreus; Neobacillus rhizophilus; Rhizosphere soil.

MeSH terms

  • Bacillaceae* / genetics
  • Bacterial Typing Techniques
  • Cardiolipins
  • Citrus*
  • DNA, Bacterial / genetics
  • Fatty Acids / chemistry
  • Phosphatidylethanolamines
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Rhizosphere
  • Sequence Analysis, DNA
  • Sodium Chloride
  • Soil
  • Soil Microbiology

Substances

  • Cardiolipins
  • DNA, Bacterial
  • Fatty Acids
  • Phosphatidylethanolamines
  • RNA, Ribosomal, 16S
  • Soil
  • Sodium Chloride