Neiella holothuriorum sp. nov., isolated from the gut of a sea cucumber Apostichopus japonicus.

A Gram-stain negative, aerobic, rod-shaped bacterium, designated 126 ^T , was isolated from the intestinal content of a sea cucumber, Apostichopus japonicus, in China. Strain 126 ^T was found to grow optimally at 25-28 °C and pH 7.5-8.0 in marine 2216 E medium, with tolerance of 1-7% (w/v) NaCl. Strain 126 ^T is motile by means of one to several polar flagella. The dominant fatty acids of strain 126 ^T were identified as C _16:1 ω7c/C _16:1 ω6c (29.5%), C _18:1 ω7c/C _18:1 ω6c (19.8%) and C _16:0 (16.7%). The respiratory quinone was found to be Q-8. The polar lipid profile was found to be mainly composed of phosphatidylglycerol and phosphatidylethanolamine. The total length of the draft genome is approximately 4.2 × 10 ⁶  bp, encoding 3655 genes and 3576 coding sequences. The G + C content of the genomic DNA is 48.0%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 126 ^T belongs to the genus Neiella and is closely related to Neiella marina J221 ^T (96.5%). Genomic comparisons of 126 ^T to N. marina J221 ^T revealed that they had similar genome size, G + C content and complement of clusters of orthologous groups. However, average nucleotide identity and digital DNA-DNA hybridization values between strains126 ^T and N. marina J221 ^T was 75.5% and 19.7%, which could distinguish the strains. On the basis of these phenotypic and genotypic data, strain 126 ^T is concluded to represent a novel species, for which the name Neiella holothuriorum sp. nov. is proposed. The type strain is 126 ^T (= GDMCC 1.2530 ^T  = KCTC 82829 ^T ).
(© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)