Agromyces aureus sp. nov., isolated from the rhizosphere of Salix caprea L. grown in a heavy-metal-contaminated soil.

A Gram-reaction-positive, motile, yellow-pigmented and rod-shaped bacterial strain, designated AR33T, was isolated from the rhizosphere of Salix caprea L. growing in a former zinc/lead mining and processing site in Austria. A polyphasic approach was applied to determine its taxonomic position. 16S rRNA gene sequence analysis, and morphological and chemotaxonomic properties showed that strain AR33T belongs to the genus Agromyces. Strain AR33T had peptidoglycan type B2γ and the major menaquinones were MK-11, MK-10 and MK-12. The main branched-chain fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. Strain AR33T showed catalase and oxidase activity and multiple heavy metal resistances to zinc, lead and cadmium. The DNA G+C content was 70.1 mol%. Levels of 16S rRNA gene sequence similarity with closely related recognized species of the genus Agromyces ranged between 98 and 99 %. However, DNA-DNA hybridization between strain AR33T and the type strains of three Agromyces species showed values lower than 42 % relatedness. Therefore, differential phenotypic characteristics together with DNA-DNA relatedness suggested that strain AR33T can be recognized as representing a distinct Agromyces species, for which the name Agromyces aureus sp. nov. is proposed. The type strain is AR33T (=DSM 101731T=LMG 29235T).