Plantactinospora soyae sp. nov., an endophytic actinomycete isolated from soybean root [Glycine max (L.) Merr]

A novel actinomycete, designated strain NEAU-gxj3T, was isolated from soybean root [Glycine max (L.) Merr.] collected from Harbin, Heilongjiang Province, China, and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain NEAU-gxj3T showed highest similarity to those of Micromonospora equina Y22T (98.2 %) and Plantactinospora endophytica YIM 68255T (98.0 %). Phylogenetic analysis based on the 16S rRNA gene and gyrB gene demonstrated that the isolate clustered with the members of the genus Plantactinospora. The chemotaxonomic properties of strain NEAU-gxj3Twere also consistent with those of members of the genus Plantactinospora. The cell wall contained meso-diaminopimelic acid and whole-cell sugars were xylose, glucose and galactose. The predominant menaquinones were MK-10(H6), MK-9(H8), MK-10(H2) and MK-10(H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were identified as anteiso-C17 : 0, iso-C16 : 0, iso-C15 : 0 and C15 : 0. A combination of DNA-DNA hybridization result and some phenotypic characteristics indicated that strain NEAU-gxj3Tcould be differentiated clearly from its closest phylogenetic relatives. Therefore, the strain is concluded to represent a novel species of the genus Plantactinospora, for which the name Plantactinospora soyae sp. nov. is proposed. The type strain is NEAU-gxj3T (=CGMCC 4.7221T=DSM 46832T).