Paludibacillus litoralis gen. nov., sp. nov.: a novel species of a novel genus in the family Paracoccaceae, isolated from the sediment of a tidal flat located in Zhoushan, China.

Abstract

A Gram-stain-negative, aerobic and rod-shaped bacterium, designated as HZG-20^T, was isolated from a tidal flat in Zhoushan, Zhejiang Province, China. The 16S rRNA sequence similarities between strain HZG-20^T and Pikeienuella piscinae RR4-56^T, Coraliihabitans acroporae NNCM2^T, Parvibaculum indicum P31^T and Zhengella mangrovi X9-2-2^T were 98.9, 91.7, 91.0 and 91.0%, respectively. Colonies of strain HZG-20^T were 1.4 mm in diameter, milky white, round, smooth and convex after cultivating on marine agar at 30 °C for 48 h. Cells were catalase and oxidase-negative. Growth occurred at 15-37 ℃ (optimum, 28 ℃), pH 5.0-9.0 (optimum, pH 6.0-8.0) and with 0-8% (w/v) NaCl (optimum, 1-3%). It contained Menaquinone-8 (H₂) as the sole respiratory quinone, and C_16:0 (11.8-13.6%), C_18:1  ω9c (6.8-13.3%) and C_15:0 anteiso (10.9-27.7%) as the major cellular fatty acids. The main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid, one unidentified phosphoglycolipid, two unidentified glycolipids (GL1-GL2) and three unidentified lipids (L1-L3). The genome of strain HZG-20^T was 3 835 886 bp in length, comprised 3746 protein-coding genes, with DNA G+C content of 67.1 mol%. The phylogenetic and phylogenomic trees indicated that strain HZG-20^T formed an independent and stable clade with P. piscinae RR4-56^T. However, the average nucleotide identity, digit DNA-DNA hybridization and average amino acid identity values between strain HZG-20^T and P. piscinae RR4-56^T, C. acroporae NNCM2^T, P. indicum P31^T and Z. mangrovi X9-2-2^T were 81.6, 71.1, 68.7 and 69.5%; 23.0, 18.5, 17.9 and 17.5%; and 78.2, 56.8, 56.5 and 61.9%, respectively, together with distinct chemotaxonomic features, indicating strain HZG-20^T should not be assigned to known genera. As a result, a novel species of a novel genus within the family Paracoccaceae, designated as Paludibacillus litoralis gen. nov., sp. nov., was proposed. The type strain is HZG-20^T (MCCC 1K08468^T=KCTC 82692^T).