Paenibacillus lemnae sp. nov., an endophytic bacterium of duckweed (Lemna aequinoctialis)

Abstract

A Gram-stain-variable, rod-shaped and endospore-forming bacterium, designated strain L7-75, was isolated from duckweed (Lemna aequinoctialis). Cells were motile with a monopolar flagellum. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain L7-75T belonged to the genus Paenibacillus , and the closest phylogenetically related species were Paenibacillus uliginis N3/975T (98.5 % 16S rRNA gene sequence similarity), Paenibacillus purispatii ES_M17T (98.5 %), Paenibacillus lactis MB 1871T (98.2 %), Paenibacillus campinasensis 324T (97.7 %), Paenibacillus glucanolyticus S93T (97.7 %) and Paenibacillus lautus ATCC 43898T (97.4 %). Growth of strain L7-75T was observed at pH 7–10 and at 20–40 °C, and NaCl concentrations up to 5 % (w/v) were tolerated. Major cellular fatty acids included anteiso-C15 : 0, C16 : 0 and anteiso-C17 : 0 that were present at 36.0 %, 14.2 % and 10.0 % of the total cellular fatty acid profile, respectively. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidyl-N-methylethanolamine. MK-7 was the predominant menaquinone. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. The DNA G+C content was 49.1 mol% (T m). DNA–DNA relatedness values between strain L7-75T and its closest relatives ranged from 4.4 to 47.8 %. These results indicate that strain L7-75T represents a novel species of the genus Paenibacillus , for which the name Paenibacillus lemnae sp. nov. is proposed. The type strain is L7-75T ( = BCC 67838T = NBRC 109972T).