Streptomyces phaeolivaceus sp. nov. and Streptomyces broussonetiae sp. nov., isolated from the leaves and rhizosphere soil of Broussonetia papyrifera

Abstract

Two novel actinobacteria, designated strains GY16T and T44T, were isolated from the leaves and rhizosphere soil of Broussonetia papyrifera, respectively. A polyphasic approach was used for determining their taxonomic position. Results of 16S rRNA gene sequence analysis indicated that strain GY16T exhibited highest similarities to Streptomyces cinereoruber subsp. fructofermentans CGMCC 4.1593T (98.82 %), Streptomyces deccanensis KCTC 19241T (98.76 %), Streptomyces scabiei NRRL B-16523T (98.69 %), Streptomyces europaeiscabiei KACC 20186T (98.69 %) and Streptomyces rishiriensis NBRC 13407T (98.69 %), and strain T44T showed 99.2, 99.1, 99.1 and <98.7 % sequence similarities to Streptomyces filipinensis CGMCC 4.1452T, Streptomyces achromogenes subsp. achromogenes DSM 40028T, Streptomyces durhamensis DSM 40539T and other Streptomyces species, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GY16T formed an independent subclade, which indicated that strain GY16T should belong to a potential novel species; and strain T44T was closely related to S. filipinensis CGMCC 4.1452T, S. achromogenes subsp. achromogenes DSM 40028T, S. durhamensis DSM 40539T and S. yokosukanensis DSM 40224T. However, the multilocus sequence analysis evolutionary distance, average nucleotide identity and DNA–DNA hybridization values between closely related relatives were far from the species-level thresholds. In addition, phenotypic and chemotaxonomic characteristics further confirmed that strains GY16T and T44T belonged to two distinct species. Based on these results, it is concluded that the isolated strains represent novel species within the genus Streptomyces , for which the names Streptomyces phaeolivaceus sp. nov. (type strain GY16T=CICC 24807T=KCTC 49326T) and Streptomyces broussonetiae sp. nov. (type strain T44T=CICC 24819T=JCM 33918T) are proposed.