Cellulomonas citrea sp. nov., isolated from paddy soil

Abstract

Two Gram-stain-positive, facultatively anaerobic, motile, aerobic, rod-shaped and non-spore-forming actinobacteria, strains AO-9T and AO-18, were isolated from paddy soil collected from Daejeon, Republic of Korea. Colonies were smooth, lemon-yellow and circular and 0.5–0.8×2.0–2.4 µm in diameter after 3 days of incubation at 28 °C on tryptic soy agar. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains AO-9T and AO-18 belonged to the genus Cellulomonas , showing the highest sequence similarities to Cellulomonas marina FXJ8.089T (96.6 %), Cellulomonas endophytica SYSUP0004T (96.5 %), Cellulomonas gelida DSM 20111T (96.2 %), Cellulomonas uda DSM 20107T (96.1 %), Cellulomonas rhizosphaerae NEAU-TCZ24T (96.1 %), Cellulomonas composti TR7-06T (96.0 %), Cellulomonas persica JCM 18111T (96.0 %) and less than 96 % to other closely related species. The DNA–DNA hybridization values between strains AO-9T and AO-18 were 87 %. The average nucleotide identity and digital DNA–DNA hybridization values between strain AO-9T and type strains of related species of the genus Cellulomonas were 84.0–85.8 % and 20.3–20.9 %, respectively. The major cellular fatty acids are anteiso-C15:0 (49.9 %), C14:0 (12.9 %) and iso-C14:0 (12.1 %). The predominant isoprenoid quinone was MK-9 (H4). The polar lipid profile consists of diphosphatidylglycerol, phosphatidylglycerol and one unidentified lipid. The DNA G+C content was 72.9 mol%. Based on its distinctive phenotypic, phylogenetic and chemotaxonomic characteristics, the two strains are considered to represent novel species of the genus Cellulomonas , for which the name Cellulomonas citrea sp. nov. is proposed. The type strain is AO-9T (=KACC 19069T=NBRC 112523T).