We carried out a polyphasic taxonomic study on a new halophilic strain designated 3(2)T, isolated from Meighan wetland, Iran. Cells of the novel strain were Gram-stain-negative, non-hemolytic, catalase- and oxidase-positive, rod-shaped, non-endospore-forming and motile. Cell growth occurred at 3-15 % NaCl (w/v; optimum, 5 %), pH 7.0-9.0 (optimum, pH 7.5-8.0) and 15-35 °C (optimum, 30 °C). 16S rRNA gene sequence comparisons confirmed the affiliation of strain 3(2)T to the class Gammaproteobacteria and the genus Halomonas with highest similarity to Halomonas daqiaonensis YCSA28T (98.4 %) and Halomonas ventosae Al12T (97.9 %). Experimental and in silico DNA-DNA hybridization values were 42.7 and 35.1% with H. daqiaonensis IBRC-M 10931T and 48 and 35.2% with H. ventosae IBRC-M 10566T, respectively, and indicated that they are different members of the same genus. The genome of the type strain was characterized by a size of 3.83 Mbp with 63 scaffolds and a G+C content of 64.8 mol%. Moreover, the average nucleotide identity values against H. ventosae Al12T and H. daqiaonensis YCSA28T were 88.8 and 88.5 %, respectively. The predominant respiratory quinone was Q-9 (92 %) with Q-8 (8 %) as a minor component. Major fatty acids were C16 : 0 cyclo, C19 : 0 ω8c, C16 : 1 ω7c and/or iso-C15:0 2-OH, C12 : 0 3-OH and C18 : 1 ω7c. The polar lipid profile of the strain contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphoaminoglycolipid and four unidentified phospholipids. According to our results, strain 3(2)T could be classified as a novel species in the genus Halomonas for which the name Halomonas lysinitropha sp. nov. is proposed. The type strain is 3(2)T (=IBRC M 10929T=LMG 29450T=CIP 111708T).
Keywords: Gram-stain-negative; Halomonadaceae; Iran; hypersaline wetland; slightly halophilic bacterium.