Cysteiniphilum litorale gen. nov., sp. nov., isolated from coastal seawater.

A taxonomic study was performed on strain SYSU D3-2T, isolated from coastal seawater near the estuary of Pearl River in southern China. The strain was observed to be Gram-reaction-negative, non-motile and non-spore-forming. Cells were found to be of coccobacilli shape. Chemotaxonomic analysis of the plasma membrane revealed ubiquinone-8 as the respiratory quinone, diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminolipid, an unidentified aminophospholipid and an unidentified phospholipid as the polar lipids, and anteiso-C15 : 0, C18 : 0 and anteiso-C17 : 0 as the major fatty acids (>10 % of total fatty acids). Comparison of 16S rRNA gene sequences showed that strain SYSU D3-2T shared maximum similarities with Caedibacter taeniospiralis 51T (92.3 %) and Fangia hongkongensis UST040201-002T (90.6 %), while sharing 85.8-90.0 % similarity with species of the genera Allofrancisella and Francisella. Phylogenetic dendrograms based on the 16S rRNA gene sequences showed that the strain clustered within the family Francisellaceae, but formed a separate lineage closely linked to Caedibactertaeniospiralis 51T and F. hongkongensis UST040201-002T. Based on the findings of the polyphasic taxonomic study, strain SYSU D3-2T is proposed to be recognized as a representative of a novel species of a new genus within the order Thiotrichales, with the name Cysteiniphilum litorale gen. nov., sp. nov. The type strain of the type species is SYSU D3-2T (=NBRC 112441T=DSM 101832T=KCTC 52386T=CGMCC 1.15758T).