Agromyces tardus sp. nov., an actinobacterium isolated from the rhizosphere soil of wheat (Triticum aestivum L.).

Abstract

A Gram-stain-positive, aerobic, heterotrophic, non-spore-forming and rod-shaped strain, designated SJ-23T, was isolated from rhizosphere soil of wheat (Triticum aestivum L.) collected from Langfang, Hebei Province, central PR China and characterized using a polyphasic approach. Morphological and chemotaxonomic characteristics were consistent with those of members of the genus Agromyces. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, glycolipid and three unidentified lipids. The predominant menaquinones detected were MK-12, MK-11 and MK-10. Major fatty acids were identified as anteiso-C17 : 0, anteiso-C15 : 0 and iso-C16 : 0. The 16S rRNA gene sequence analysis showed that strain SJ-23T belongs to the genus Agromyces with high sequence similarities to Agromyces ramosus DSM 43045T (99.2 %), Agromycescerinussubsp. cerinus DSM 8595T (98.8 %) and Agromyces cerinussubsp. nitratus DSM 8596T (98.6 %). Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain formed a separate branch in the genus Agromyces. Furthermore, the combination of DNA-DNA hybridization results and some phenotypic characteristics demonstrated that strain SJ-23T could be distinguished from its closest relatives. Therefore, it is proposed that strain SJ-23T represents a novel species of the genus Agromyces, for which the name Agromycestardus sp. nov. is proposed. The type strain is SJ-23T (=CGMCC 4.7419T=DSM 105049T).