Description of Halopseudomonas maritima sp. nov., based on phylogenomic analysis

Abstract

A novel bacterium, strain RR6T of the genus Halopseudomonas, was isolated from the sea sand from Paradip port area, India. Cells are Gram-stain-negative, rod-shaped, aerobic, non-sporulating and motile. The major cellular fatty acids of RR6T were C10:0 3OH, C12:0, C16:1 w7c/16:1 w6c, 18:1 w7c and/or 18:1 w6c and C16:0. The predominant polar lipids were phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylcholine (PC), unidentified phospholipid (PL) and unidentified lipids (L1-L2). The genome size of the strain RR6 was 3.93 Mb. The genomic G+C content was 61.3%. Gene ontology study showed a significant fraction of genes were associated with biological processes (53%), followed by molecular function (36%) and cellular components (11%). Comparisons of 16S rRNA gene sequences revealed 99.73 - 99.87 % sequence similarity with the closely related type strains of the genus Halopseudomonas. The average nucleotide identity (ANI) and average amino acid identity (AAI) of RR6T with reference strains of closely related species of the genus Halopseudomonas were below 95-96, and the corresponding in-silico DNA-DNA hybridization (DDH) values were below 70 %. A phylogenomic tree based on core genome analysis supported these results. Genotypic and phenotypic characteristics of RR6T indicate that the strain represents a novel species of the genus Halopseudomonas and the name Halopseudomonas maritima sp. nov. is proposed. The type strain is RR6T (= NBRC 115418T = TBRC 15628T).