A novel endophytic actinobacterium, designated strain 8BXZ-J1T, was isolated from surface-sterilized branches of Thespesia populnea collected from Beilun Estuary Mangrove Forest National Nature Reserve in Guangxi, China, and examined by a polyphasic approach to determine its taxonomic position. Cells of the isolate were Gram-stain-positive, aerobic, non-spore-forming, non-motile and short rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain 8BXZ-J1T belonged to the genus Marmoricola, sharing highest similarity with Marmoricola solisilvae DSM 27140T (96.9 %). The isolate grew at 10-35 °C (optimum, 28-30 °C), at pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0-10 % (w/v) NaCl (optimum, 0-5.0 %). The organism contained ll-2,6-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan, MK-8(H4) as the major menaquinone, and a polar lipid profile including diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol and two unknown lipids. The major fatty acids of strain 8BXZ-J1T were C18 : 0 10-methyl, iso-C16 : 0 and C16 : 0. The G+C content of the genomic DNA was 68.7 mol%. These data demonstrate that strain 8BXZ-J1T is representative of a novel species of the genus Marmoricola, for which the name Marmoricola endophyticus sp. nov. is proposed. The type strain is 8BXZ-J1T (=KCTC 39789T=CGMCC 1.16067T).
Keywords: Marmoricola; actinobacteria; endophytic; polyphasic identification.