Chengkuizengella axinellae sp. nov., a symbiotic bacterium isolated from a marine sponge of the genus Axinella.

A Gram-stain-positive, strictly aerobic, creamy-white colored, endospore-forming and non-motile rods strain, designated as strain 2205SS18-9, was isolated from a marine sponge, Axinella sp. collected from Seopseom Island, Republic of Korea. Optimal growth of strain 2205SS18-9 was observed at 25-30 °C, pH 6.5-7.0, and in the presence of 3.0% (w/v) NaCl. Cells were oxidase-positive and catalase-negative. Negative for nitrate reduction and indole production. Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain 2205SS18-9 formed a distinct phyletic lineage in the genus Chengkuizengella, and it was most closely related to Chengkuizengella marina YPA3-1-1 and Chengkuizengella sediminis J15A17 with 97.1 and 96.6% 16S rRNA gene sequence similarities, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain 2205SS18-9 and Chengkuizengella marina YPA3-1-1 were 79.0 and 21.6%, respectively. The genomic DNA G + C content was 34.1%. The genome harbors a number of host-adhesion and transporter genes, suggested that strain 2205SS18-9 may interact with its sponge host as a symbiont. Menaquinone-7 was the sole isoprenoid quinone and antieiso-C (28.5%), iso-C (25.8%), C ω7c alcohol (15.0%), and iso-C (11.2%) were detected as the major fatty acids. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, and an unidentified lipid. The cell-wall peptidoglycan contained lysine, alanine, glutamate, and aspartate. Based on these analyses, strain 2205SS18-9 represents a novel species of the genus Chengkuizengella, for which the name Chengkuizengella axinellae sp. nov. is proposed. The type strain is 2205SS18-9 (= KACC 23238 = LMG 33063).