Thalassobacillus cyri sp. nov., a moderately halophilic Gram-positive bacterium from a hypersaline lake

Abstract

A Gram-positive, moderately halophilic bacterium, designated strain HS286(T), was isolated from water of the hypersaline Lake Howz-Soltan in Iran. Cells were strictly aerobic, rod-shaped, motile and able to produce ellipsoidal endospores at a central-subterminal position in swollen sporangia. Isolate HS286(T) grew in a complex medium supplemented with 1-15 % (w/v) NaCl, with optimum growth at 8.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that strain HS286(T) was closely related to Thalassobacillus devorans G-19.1(T) (99.4 % gene sequence similarity). The other closest species were Halobacillus yeomjeoni MSS-402(T) (96.9 %) and other species of the genus Halobacillus (with 96.7-93.5 % similarity). Strain HS286(T) had cell-wall peptidoglycan based on meso-diaminopimelic acid and MK-7 as the respiratory isoprenoid quinone. The major fatty acids were anteiso-C(15 : 0) (43.8 %), iso-C(16 : 0) (21.4 %), iso-C(14 : 0) (9.4 %), anteiso-C(17 : 0) (8.7 %) and iso-C(15 : 0) (7.0 %) and the polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, two phospholipids and a glycolipid. The DNA G+C content was 43.0 mol%. All of these features confirmed the placement of isolate HS286(T) within the genus Thalassobacillus. However DNA-DNA hybridization between strain HS286(T) and the only recognized species of the genus Thalassobacillus, T. devorans G-19.1(T), was 27.3 %, showing unequivocally that the novel isolate constituted a new genospecies. Strain HS286(T) could be clearly differentiated from T. devorans and other phylogenetic neighbours on the basis of several phenotypic, genotypic and chemotaxonomic features. Therefore, strain HS286(T) constitutes a novel species, for which the name Thalassobacillus cyri sp. nov. is proposed. The type strain is HS286(T) (=CCM 7597(T)=JCM 15722(T)).