Phycicola gilvus gen. nov., sp. nov., an actinobacterium isolated from living seaweed

Abstract

A Gram-positive, aerobic, non-mycelium-forming actinomycete, designated strain SSWW-21(T), was isolated from a living seaweed sample on the coast of Jeju, Republic of Korea. Cells of the organism were rod-shaped or coccoid depending on culture age. Short rods were observed in young cultures, whereas older cultures predominantly consisted of coccoid cells. Rod-shaped cells were motile by means of flagella, but coccoid cells were non-motile. Budding-like cell division was observed. The temperature and pH for growth were 4-30 degrees C and pH 6.1-10.1. Growth occurred in the presence of up to 2 % NaCl. Phylogenetic analyses showed that the organism formed a distinct clade within the family Microbacteriaceae. Comparative 16S rRNA gene sequence analyses showed that strain SSWW-21(T) was related most closely to the type strains of Okibacterium fritillariae (96.8 % similarity), Leifsonia poae (96.8 %) and Agreia bicolorata (96.6 %). Levels of 16S rRNA gene sequence similarity between the new isolate and members of other genera within the family Microbacteriaceae were in the range 93.1-96.3 %. The cell-wall peptidoglycan of strain SSWW-21(T) was of the B-type (2,4-diaminobutyric acid as the diagnostic diamino acid). The acyl type of the muramic acid was acetyl. The predominant menaquinone was MK-11. The polar lipid profile contained phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol and diphosphatidylglycerol. Mycolic acids were not present. The major cellular fatty acids were saturated branched-chain components (anteiso-C(15 : 0) and anteiso-C(17 : 0)). The G+C content of the DNA was 69.8 mol%. On the basis of the phenotypic and phylogenetic data presented, strain SSWW-21(T) is considered to represent a novel species of a new genus within the family Microbacteriaceae, for which the name Phycicola gilvus gen. nov., sp. nov. is proposed. The type strain of Phycicola gilvus is SSWW-21(T) (=KCTC 19185(T) =DSM 18319(T)).