Spirosoma oryzae sp. nov., isolated from rice soil and emended description of the genus Spirosoma

Abstract

A bacterial strain, designated RHs22T, was isolated from a soil sample cultivated with rice in the Suwon region of South Korea. The cells were aerobic, Gram-stain-negative, non-spore-forming, non-flagellated rods or occasionally filaments. The strain grew at 10–37 °C (optimum, 28–30 °C), at pH 5.0–10.0 (optimum, 7.0) and in the presence of 0–1 % (w/v) NaCl (optimum, 0 %). Phylogenetically, the strain was closely related to members of the genus Spirosoma , as its 16S rRNA gene sequence had similarity of 90.3–92.1 % with respect to those of members of the genus Spirosoma , showing the highest sequence similarity with Spirosoma panaciterrae DSM 21099T. Strain RHs22T revealed relatively low sequence similarities of less than 90 % with all the other species with validly published names. It contained MK-7 as the predominant menaquinone and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 1ω5c, iso-C15 : 0 and iso-C17 : 0 3-OH as the main fatty acids. The polar lipids of strain RHs22T were phosphatidylethanolamine, one unknown aminolipid, two unknown aminophospholipids, one unknown phospholipid and five unknown lipids. The DNA G+C content was 57.0 mol%. Phylogenetic, phenotypic and chemotaxonomic data obtained in this study indicate that strain RHs22T represents a novel species of the genus Spirosoma , for which the name Spirosoma oryzae sp. nov. is proposed. The type strain is RHs22T ( = KACC 17324T = DSM 28354T). An emended description of the genus Spirosoma is also proposed.