Bacillus graminis sp. nov., an endophyte isolated from a coastal dune plant

Abstract

A Gram-stain-positive endophytic bacterium, designated strain YC6957T, was isolated from surface-sterilized roots of a halophyte (Elymus mollisTrin.) inhabiting coastal tidal flats of Namhae Island, located on the southern coast of Korea, and was subjected to a polyphasic taxonomic study. Cells were facultatively anaerobic, endospore-forming rods to coccoid rods, motile by a single flagellum. Strain YC6957Twas catalase-positive, oxidase-negative and able to grow in the presence of 0–8 % (w/v) NaCl, with optimum growth at 4–5 % (w/v) NaCl. Growth occurred at 15–45 °C (optimal growth at 30–35 °C) and pH 6.0–8.5 (optimal growth at pH 7.0–8.0). The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major cellular fatty acids were C16 : 0(11.3 %), iso-C15 : 0(19.2 %) and anteiso-C15 : 0(36.4 %). The cell-wall peptidoglycan containedmeso-diaminopimelic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 41.6 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the isolate belonged to the genusBacillus. Strain YC6957Texhibited high 16S rRNA gene sequence similarity to its closest neighbours,Bacillus rurisLMG 22866T(96.14 %),Bacillus lentusNCIMB 8773T(95.97 %) andBacillus galactosidilyticusLMG 17892T(95.91 %), and less than 95.84 % similarity to all other type strains in the genusBacillus. On the basis of the phylogenetic, physiological and biochemical data, it is suggested that strain YC6957Trepresents a novel species of the genusBacillus, for which the nameBacillus graminissp. nov. is proposed. The type strain is YC6957T( = KACC 13779T = DSM 22162T).