Pseudoalteromonas neustonica sp. nov., isolated from the sea surface microlayer of the Ross Sea (Antarctica), and emended description of the genus Pseudoalteromonas.

A Gram-stain-negative, facultatively anaerobic, rod-shaped and motile strain, designated PAMC 28425T, was isolated from a sea surface microlayer sample from the Ross Sea, Antarctica. Analysis of the 16S rRNA gene sequence of strain PAMC 28425T showed an affiliation with the genus Pseudoalteromonas. Phylogenetic analyses revealed that strain PAMC 28425T formed a clade with Pseudoalteromonas prydzensis MB8-11T and Pseudoalteromonas mariniglutinosaKMM 3635T with 16S rRNA gene sequence similarities of 98.3-98.6 %. Genomic relatedness analyses based on the average nucleotide identity and the genome-to-genome distance showed that strain PAMC 28425T is clearly distinguished from the phylogenetically close relatives. Cells of strain PAMC 28425T grew optimally at 25 °C and pH 7.5-8.5 in the presence of 1.0-3.0 % (w/v) sea salts. The major cellular fatty acids (>10 %) were C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, and C18 : 1ω6c and/or C18 : 1ω7c. The genomic DNA G+C content was 39.7 mol%. On the basis of the phylogenetic, genomic, chemotaxonomic and phenotypic data presented, we propose the name Pseudoalteromonas neustonica sp. nov. with the type strain PAMC 28425T (=KCCM 43187T=JCM 31286T).