Amnibacterium setariae sp. nov., an endophytic actinobacterium isolated from dried foxtail

Abstract

A Gram-stain positive, short rod-shaped, aerobic, motile by means of gliding, yellow-pigmented actinobacterium, designated strain DD4a(T), was isolated from dry yellow foxtail. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DD4a(T) is closely related to Amnibacterium soli MB78(T) (98.4% similarity), Amnibacterium kyonggiense KSL51201-037(T) (98.2%) and Amnibacterium endophyticum 1T4Z-3(T) (97.43%). Strain DD4a(T) forms yellow colonies on R2A agar medium. The peptidoglycan was found to contains diaminopimelic acid (which is a diagnostic cell wall diamino acid), alanine, glutamic acid and lysine. The polar lipids diphosphatidylglycerol, phosphatidylglycerol, six unidentified glycolipids and an unidentified polar lipid were found to be present in strain DD4a(T). The major cellular fatty acids anteiso-C-15:0 (42.9%) and iso-C-16:0 (34.6%) were found in strain DD4a(T). The predominant respiratory quinones were found to be MK-11 and MK-12. The DNA G+C content of strain DD4a(T) is 73.9 mol%. DNA-DNA relatedness of strain DD4a(T) with A. soli MB78(T), A. kyonggiense KSL51201-037(T), and A. endophyticum 1T4Z-3(T) were 53.3% (+/- 1.1%), 47.0% (+/- 0.5%), and 47.9% (+/- 0.9%), respectively. The digital DNA-DNA hybridisation and average nucleotide identity values between strain DD4a(T) and A. kyonggiense KSL51201-037(T) were determined to be 26.1% and 82.7%. On the basis of phenotypic, genotypic, chemotaxonomic and phylogenetic analysis, DD4a(T) represents a novel member of the genus Amnibacterium, for which the name Amnibacterium setariae sp. nov., is proposed. The type strain of Amnibacterium setariae is DD4a(T) (=KACC 19817(T)=JCM 32878(T)).