Genome taxonomy of the genus Neptuniibacter and proposal of Neptuniibacter victor sp. nov. isolated from sea cucumber larvae

PLoS One. 2023 Aug 15;18(8):e0290060. doi: 10.1371/journal.pone.0290060. eCollection 2023.


A Gram-staining-negative, oxidase-positive, strictly aerobic rod-shaped bacterium, designated strain PT1T, was isolated from the laboratory-reared larvae of the sea cucumber Apostichopus japonicus. A phylogenetic analysis based on the 16S rRNA gene nucleotide sequences revealed that PT1T was closely related to Neptuniibacter marinus ATR 1.1T (= CECT 8938T = DSM 100783T) and Neptuniibacter caesariensis MED92T (= CECT 7075T = CCUG 52065T) showing 98.2% and 98.1% sequence similarity, respectively. However, the average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) values among these three strains were 72.0%-74.8% and 18.3%-19.5% among related Neptuniibacter species, which were below 95% and 70%, respectively, confirming the novel status of PT1T. The average amino acid identity (AAI) values of PT1T showing 74-77% among those strains indicated PT1T is a new species in the genus Neptuniibacter. Based on the genome-based taxonomic approach, Neptuniibacter victor sp. nov. is proposed for PT1T. The type strain is PT1T (JCM 35563T = LMG 32868T).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Typing Techniques
  • DNA
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Fatty Acids* / analysis
  • Larva / genetics
  • Nucleic Acid Hybridization
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Sea Cucumbers* / genetics
  • Sequence Analysis, DNA


  • Fatty Acids
  • RNA, Ribosomal, 16S
  • DNA
  • DNA, Bacterial

Grants and funding

This study was supported by Kaken 19K22262. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.