Marmoricola Mangrovicus Sp. Nov., An Endophytic Actinobacterium Isolated From Kandelia Candel

A Gram-stain-positive, aerobic, motile, non-spore-forming and rod-shaped actinobacterium, designated strain 4Q3S-7(T), was isolated from a piece of surface-sterilized bark of Kandelia candel collected at the Cotai Ecological Zone in Macao, China. Colonies were yellowish white, circular, smooth and convex. The 16S rRNA gene sequence of strain 4Q3S-7(T) exhibited highest similarities to Marmoricola ginsengisoli Gsoil 097(T) (97.6 %), Marmoricola solisilvae KIS18-7(T) (97.6 %) and Marmoricola pocheonensis Gsoil 818(T) (97.3 %). Phylogenetic analysis showed that strain 4Q3S-7(T) clustered with species of the genus Marmoricola and was clearly affiliated to the genus Marmoricola. Genomic analyses, including average nucleotide identity and DNA-DNA hybridization, clearly separated strain 4Q3S-7(T) from M. ginsengisoli Gsoil 097(T), M. solisilvae KIS18-7(T) and M. pocheonensis Gsoil 818(T) with values below the thresholds for species delineation. Strain 4Q3S-7(T) had LL-2,6-diaminopimelic acid as the diagnostic diamino acid in the cell wall. The major fatty acids (>10 % of total fatty acids) were C-18(:0) 10-methyl (TBSA), C-18:1 omega 9c, iso-C-16:0 and iso-C-16:0 2-OH. The predominant menaquinone was MK-8(H-4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol and an unidentified phospholipid. The DNA G+C content of strain 4Q3S-7(T) was 72.0 mol% (draft genome sequence). Based on its phylogenetic, phenotypic and chemotaxonomic features, strain 4Q3S-7(T) is considered to represent a novel species of the genus Marmoricola, for which the name Marmoricola mangrovicus sp. nov. is proposed. The type strain is 4Q3S-7(T) (=KCTC 39790(T)=CGMCC 4.7424(T)).