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).