Nucisporomicrobium flavum gen. nov., sp. nov., a new member of the family Micromonosporaceae isolated from saline-alkali soil

A Gram-stain-positive, aerobic actinobacterium, designated strain NEAU-24(T), was isolated from saline-alkali soil collected from Daqing City, Heilongjiang Province, PR China. Strain NEAU-24(T) was found to produce abundant substrate mycelia but no aerial hyphae. The substrate mycelia formed irregular pseudosporangia consisting of nuciform spores, and the surface of the spores was smooth. 16S rRNA gene sequence analysis showed that strain NEAU-24(T) clustered with Pseudosporangium ferrugineum 3-44-a(19)(T), Couchioplanes caeruleus subsp. azureus DSM 44103T and C. caeruleus subsp. caeruleus DSM 43634(T) within the family Micromonosporaceae and was most closely related to P. ferrugineum 3-44-a(19)(T) (99.17 %). The strain contained meso-diaminopimelic acid as the cell-wall diamino acid and MK-9(H-6) as the menaquinone. The whole cell sugar profile consisted of glucose, galactose, xylose and arabinose. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, phosphatidylinositol and an unidentified lipid. The major fatty acids were summarized as C-16:0, C-15:0, C-17:0, iso-C-16:0 and iso-C-17:0. The low digital DNA-DNA hybridization and average nucleotide identity values could differentiate strain NEAU-24(T) from its related type strains. The phenotypic, genetic and chemotaxonomic data also indicated that strain NEAU-24(T) occupied a branch separated from those of known genera in the family Micromonosporaceae. In addition, genomic analysis confirmed that strain NEAU-24(T) had the potential to produce chitinase. Therefore, strain NEAU-24(T) represents a novel species of a new genus and species in the family Micromonosporaceae, for which the name Nucisporomicrobium flavum gen. nov., sp. nov. is proposed. The type strain of Nucisporomicrobium flavum is NEAU-24(T) (=CCTCC AA 2020016(T)=JCM 33973(T)).

Automated summary

A novel Gram-stain-positive, aerobic actinobacterium, designated Nucisporomicrobium flavum, was isolated from saline-alkali soil collected from Daqing City, Heilongjiang Province, PR China. Genetic and phenotypic analysis showed that this strain is distinct from known genera within the family Micromonosporaceae.