Pseudomonas fluvialis sp. nov., a novel member of the genus Pseudomonas isolated from the river Ganges, India

Abstract

A bacterial strain, designated ASS-1T, was isolated and identified from a sediment sample of the river Ganges, Allahabad, India. The strain was Gram-stain-negative, formed straw-yellow pigmented colonies, was strictly aerobic, motile with a single polar flagellum, and positive for oxidase and catalase. The major fatty acids were C16 : 1ω7c/ 16 : 1 C16 : 1ω6c, C18 : 1ω7c and C16 : 0. Sequence analysis based on the 16S rRNA gene revealed that strain ASS-1T showed high similarity to Pseudomonas guguanensis CC-G9AT (98.2 %), Pseudomonas alcaligenes ATCC 14909T (98.2 %), Pseudomonas oleovorans DSM 1045T (98.1 %), Pseudomonas indolxydans IPL-1T (98.1 %) and Pseudomonas toyotomiensis HT-3T (98.0 %). Analysis of its rpoB and rpoD housekeeping genes confirmed its phylogenetic affiliation and showed identities lower than 93 % with respect to the closest relatives. Phylogenetic analysis based on the 16S rRNA, rpoB, rpoD genes and the whole genome assigned it to the genus Pseudomonas . The results of digital DNA–DNA hybridization based on the genome-to-genome distance calculator and average nucleotide identity revealed low genome relatedness to its close phylogenetic neighbours (below the recommended thresholds of 70 and 95 %, respectively, for species delineation). Strain ASS-1T also differed from the related strains by some phenotypic characteristics, i.e. growth at pH 5.0 and 42 °C, starch and casein hydrolysis, and citrate utilization. Therefore, based on data obtained from phenotypic and genotypic analysis, it is evident that strain ASS-1T should be regarded as a novel species within the genus Pseudomonas , for which the name Pseudomonas fluvialis sp. nov. is proposed. The type strain is ASS-1T (=KCTC 52437T=CCM 8778T).