Description and Genome-Based Analysis of Vibrio chaetopteri sp. nov., a New Species of the Mediterranei Clade Isolated from a Marine Polychaete

• DOI: 10.3390/microorganisms13030638
• Publication Date: 2025-03-11T20:39:03Z
• Authors: Valeriya Kurilenko; Evgenia Bystritskaya; Nadezhda Otstavnykh; Peter Velansky; Darina Lichmanuk; Yulia Savicheva; Lyudmila Romanenko; Marina Isaeva

Two novel strains, CB1-14T and CB2-10, were isolated from the marine polychaetes Chaetopterus cautus from the Sea of Japan. Phylogenetic analysis based on the 16S rRNA sequences revealed that the two strains belong to the genus Vibrio, sharing 98.96% identity with Vibrio hangzhouensis CN 83T. MLSA using five protein-coding genes (ftsZ, gyrA, gyrB, mreB, and rpoA) showed that CB1-14T and CB2-10 are closely related to the members of the Mediterranei clade, namely Vibrio mediterranei CECT 621T, Vibrio barjaei 3062T, Vibrio thalassae CECT 8203T, Vibrio hangzhouensis CGMCC 1.7062T, Vibrio maritimus CAIM 1455T, and Vibrio variabilis CAIM 1454T. Based on both MLST neighbor-net phylogenetic network and phylogenomic tree results, they fell into the subclade formed by V. maritimus CAIM 1455T and V. variabilis CAIM 1454T. Both new strains CB1-14T and CB2-10 showed the highest ANI/AAI values of 91.3%/92.7% with V. variabilis CAIM 1454T and 90.3%/93.1% with V. maritimus CAIM 1455T. The dDDH values between strain CB1-14T and the members of the Mediterranei clade ranged from 20.9% to 45.7%. Major fatty acids were C16:1ω9c, C16:1ω7c, and C18:1ω9c, followed by C16:0 and C18:1ω7c. The genome of CB1-14T is 5,591,686 bp in size, with DNA G+C content of 46.1%. It consists of two circular chromosomes (3,497,892 and 1,804,652 bp) and one plasmid (241,015 bp) and comprises 4782 protein-coding genes and 10 rrn operons. The CB1-14T and CB2-10 genomes were enriched in CAZyme-encoding genes of the following families: GH1, GH3, GH13, GH23, GH43, GH94, PL17, and CE4, indicating the potential to catabolize alginate, xylan, and chitin, common polysaccharides in marine ecosystems. Based on the combined phylogenomic analyses and phenotypic properties, a new species, Vibrio chaetopteri sp. nov., is proposed, with CB1-14T = (KMM 8419T = KCTC 92790T) as the type strain.