Agromyces humi sp. nov., actinobacterium isolated from farm soil

Abstract

A Gram-stain-positive actinobacterial strain, designated ANK073T, was isolated from rhizosphere soil sampled at a spinach farming field in Shinan, Republic of Korea. Cells of strain ANK073T were found to be aerobic, non-motile, non-spore-forming rods which could grow at 20–40 °C (optimum, 30 °C), at pH 6.0–10.0 (optimum, pH 6.5–7.5) and at salinities of 0–4 % (w/v) NaCl (optimum, 0 % NaCl). The 16S rRNA gene sequence analysis showed that strain ANK073T belongs to the genus Agromyces with high sequence similarities to Agromyces humatus CD5T (98.8 %), Agromyces tardus SJ-23T (98.5 %) and Agromyces iriomotensis IY07-20T (98.4 %). The phylogenetic analysis indicated that strain ANK073T formed a distinct phyletic line in the genus Agromyces and the results of DNA–DNA relatedness and phylogenomic analysis based on whole genome sequences demonstrated that strain ANK073T could be separated from its closest relatives in the genus Agromyces . The strain contained 2,4-diaminobutylic acid, glycine, d-glutamic acid and d-alanine in the peptidoglycan. The predominant menaquinones were identified as MK-12 and MK-11, and the major fatty acids were anteiso-C17 : 0, anteiso-C15 :  0 and iso-C15:0. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The G+C content of the genome was determined to be 70.2 mol%. On the basis of its phenotypic and chemotaxonomic properties and the results of phylogenetic and phylogenomic analyses, strain ANK073T is considered to represent a novel species in the genus Agromyces , for which the name Agromyces humi sp. nov. is proposed. The type strain is ANK073T (=KACC 18683T=NBRC 111825T).