Actinocorallia populi sp nov., an endophytic actinomycete isolated from a root of Populus adenopoda (Maxim.)

An endophytic actinobacterium, strain A251(T), was isolated from the root of Populus adenopoda Maxim and subjected to characterization using polyphasic taxonomy. Analysis of the 16S rRNA gene sequence revealed that the isolate represented a member of the phylogenetic cluster of the genus Actinocorallia and was most closely related to Actinocorallia aurantiaca JCM 8201(T) (98.0 %) and Actinocorallia libanotica IFO 10495(T) (98.0 %). DNA-DNA hybridization values between A251(T) and these strains were 41.2 % and 45.0 %, respectively. The G+C content of the DNA was 71.5 mol%. Major fatty acids were C-16:0, C-16:1 t,omega 7c and C-18:1 omega 9c. The peptidoglycan diamino acid of A251(T) was meso-diaminopimelic acid and the whole-cell hydrolysates contained glucose and ribose. The major menaquinones were MK-9(H-4) and MK-9(H-6). The phospholipid profile included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, an undefined aminophospholipid and two undefined phospholipids. DNA-DNA hybridization data in combination with differences in the biochemical and physiological properties, indicated that A251(T) should be classified as representing a novel species within the genus Actinocorallia, for which the name Actinocorallia populi sp. nov. is proposed, with A251(T) (=CGMCC 4.7421(T) =JCM 32178(T)) as the type strain.