Neutrotolerant acidophilic Streptomyces species isolated from acidic soils in China: Streptomyces guanduensis sp. nov., Streptomyces paucisporeus sp. nov., Streptomyces rubidus sp. nov. and Streptomyces yanglinensis sp. nov.

The taxonomic status of six neutrotolerant acidophilic streptomycetes isolated from acidic soils in Yunnan Province, China, was established using a polyphasic approach. The morphological and chemotaxonomic characteristics revealed that the isolates belong to the genus Streptomyces. Almost complete 16S rRNA gene sequences of the isolates were determined and aligned with available corresponding sequences of representatives of the family Streptomycetaceae; phylogenetic trees were inferred using four tree-making algorithms. The isolates formed a distinct, albeit heterogeneous, subclade in the Streptomyces 16S rRNA gene tree together with the type strain of Streptomyces yeochonensis, but were readily distinguishable from the latter using DNA-DNA hybridization and phenotypic data. It was evident from the genotypic and phenotypic data that the isolates belonged to four novel Streptomyces species, for which the following names are proposed: Streptomyces guanduensis sp. nov. (type strain 701T=CGMCC 4.2022T=JCM 13274T), Streptomyces paucisporeus sp. nov. (type strain 1413T=CGMCC 4.2025T=JCM 13276T), Streptomyces rubidus sp. nov. (type strain 13c15T=CGMCC 4.2026T=JCM 13277T) and Streptomyces yanglinensis sp. nov. (type strain 1307T=CGMCC 4.2023T=JCM 13275T); isolates 317 and 913 belong to this latter species.