Streptomyces populi sp nov., a novel endophytic actinobacterium isolated from stem of Populus adenopoda Maxim

A novel endophytic actinobacterium strain, designated A249(T), was isolated from the stem of Populus adenopoda collected at Mount Qingcheng in south-west China. Its taxonomic position was determined by using a polyphasic approach. The cultural and morphological characteristics of isolate A249(T) were consistent with members of the genus Streptomyces. Growth occurred at 10-37(degrees)C, pH 6.0-12.0 and in the presence of 0-4% (w/v) NaCl. Analysis of the 16S rRNA gene sequence and phylogenetic trees showed the closest phylogenetic relatives to strain A249(T) were Streptomyces shaanxiensis JCM 16925(7) (98.0 % 16S rRNA gene sequence similarity) and Streptomyces lanatus JCM 4332(T) (97.9 %). The DNA-DNA hybridization values between the strain A249(T) and the two reference strains ranged from 41.4 to 49.4%. The DNA G+Ccontent was 71.7 mol%. The range of average nucleotide identity values was 81.5-86.7 %. Chemical analysis of cellular components indicated that strain A249(T) contained LL-diaminopimelic acid, xylose and galactose. The predominant menaquinones were MK-9(H-6) and MK-9(H-8). The polar lipids were diphosphatidylglycerol, phosphatidylinositol mannosides, phosphatidylethanolamine, two unidentified lipids, one unidentified phospholipid, one unidentified aminolipid and one unidentified aminophospholipid. The major fatty acids comprised C-(16:0), iso-C-14:0,iso-C-15:0, iso-C-16:0, anteiso-C-15:0 and C-16:1 omega 7c. On the basis of the phenotypic and genotypic differentiation of the three tested strains, isolate A249(T) is proposed to represent a novel species of the genus Streptomyces, named Streptomyces populi sp. nov. The type strain is A249(T) (=CGMCC 4.7417(t)=JCM 32175(T)).