Larsenimonas rhizosphaerae sp. nov., isolated from a tidal mudflat.

Abstract

A Gram-reaction-negative, aerobic, motile, rod-shaped bacterium, designated GH3-8T, was isolated from rhizosphere mudflats of halophytes on the seashore of Gangwha Island, Republic of Korea. Growth was observed at pH 4-10 (optimum, pH 7-8), at 4-40 °C (optimum, 37 °C) and in the presence of 0.5-20 % (w/v) NaCl (optimum, 4 %). The predominant respiratory quinone was Q-9. The major fatty acids were C18 : 1 ω7c, C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and C12 : 0 3OH. The polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, an unidentified phosphoglycolipid, an unidentified phosphoglycoaminolipid, an unidentified glycoaminolipid, two unidentified phospholipids and two unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences exhibited that the isolate belonged to the family Halomonadaceae, with the most closely related species, Larsenimonas suaedae (98.1 % sequence similarity) and Larsenimonas salina (97.9 %). Sequence similarity values between the isolate and other representatives of the family Halomonadaceae were all below 95.3 %. The values of average nucleotide identity between strain GH3-8T and members of the genus Larsenimonas were 73.42 % with L. salina CCM 8464T and 72.38 % with L. suaedae DSM 22428T. Strain GH3-8T showed digital DNA-DNA hybridization values of 18.5-18.6 % with members of the genus Larsenimonas. Based on phenotypic and chemotaxonomic distinctiveness together with low overall genomic relatedness indices and phylogenetic data, the isolate is considered to represent a new species of the genus Larsenimonas, for which the name Larsenimonas rhizosphaerae sp. nov. is proposed, with the type strain GH3-8T (=KCTC 62127T=NBRC 113214T).