Four novel Pseudoalteromonas species isolated from seawater: Pseudoalteromonas mucoides sp. nov., Pseudoalteromonas aquimarina sp. nov., Pseudoalteromonas maris sp. nov. and Pseudoalteromonas thalassia sp. nov.

Abstract

Four novel marine bacteria, ZZD1^T, SSM20^T, SSDWG2^T and SSMSWG5^T, were collected from seawater at Jajakdo and Minmeoru Beaches, Republic of Korea. The cells of these strains were Gram-stain-negative and rod-shaped. Strains ZZD1^T, SSM20^T, SSDWG2^T and SSMSWG5^T had the highest 16S rRNA gene sequence similarity to Pseudoalteromonas carrageenovora IAM 12662^T (16S rRNA gene sequence similarity, 99.1%), Pseudoalteromonas spongiae UST010723-006^T (99.2%), Pseudoalteromonas caenipelagi JBTF-M23^T (98.4%) and Pseudoalteromonas shioyasakiensis SE3^T (99.2%), respectively. Polyphasic and phylogenetic analyses confirmed that the four strains were closely related to the genus Pseudoalteromonas. The digital DNA-DNA hybridization values ranged from 18.9 to 22.2% for ZZD1^T, 19.1 to 26.0% for SSM20^T, 19.7 to 22.8% for SSDWG2^T and 19.7 to 34.5% for SSMSWG5^T. All values were thus below the 70% threshold, indicating distinct genomic differences between the strains. In addition, the average nucleotide identity and average amino acid identity of ZZD1^T, SSM20^T, SSDWG2^T and SSMSWG5^T with other species of the genus Pseudoalteromonas included in the phylogenetic analysis were 66.6-93.1% and 70.4-88.2%, respectively. Collectively, these results confirmed that the four strains represented new species within the genus Pseudoalteromonas. Based on these findings, the strains were classified as Pseudoalteromonas mucoides sp. nov. (type strain ZZD1^T=KACC 23717^T=TBRC 19020^T), Pseudoalteromonas aquimarina sp. nov. (type strain SSM20^T=KACC 23718^T=TBRC 19019^T), Pseudoalteromonas maris sp. nov. (type strain SSDWG2^T=KACC 23719^T=TBRC 19021^T) and Pseudoalteromonas thalassia sp. nov. (type strain SSMSWG5^T=KACC 23734^T=TBRC 19022^T).