Streptomyces Spinosirectus sp. nov., Isolated From the Medicinal Plant Xanthium Sibiricum.

Abstract

A novel actinobacterium, designated strain CRSS-Y-16T, was isolated from the healthy leaves of Xanthium sibiricum, in China and characterized by a polyphasic approach. This strain produced abundant aerial mycelia that generated rod-shaped spores with spiny surfaces. The cell wall contained LL-diaminopimelic acid. The major cellular fatty acids (>10.0%) were C16:0, iso-C16:0, and C18:1 ω9c. The predominant menaquinones were MK-9(H2) and MK-9(H4). The detected polar lipids were diphosphatidylglycerol, hydroxyl phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositolmannoside, phospholipids of unknown structure containing glucosamine and unidentified phospholipids. The genomic G+C content was 70.7%. The full-length 16S rRNA gene sequence analysis indicated that strain CRSS-Y-16T belonged to the genus Streptomyces and shared <98.7% sequence similarities with all recognized type species of the genus. Phylogenetic analysis based on 16S rRNA gene sequences showed that this strain formed a distinct branch. Phylogenomic analysis demonstrated that it was closely related to Streptomyces panaciradicis 1MR-8T. However, the clustering patterns resulting from phylogenomic tree verified that strain CRSS-Y-16T represented a novel Streptomyces species. This result was further confirmed by low average nucleotide identity and digital DNA-DNA hybridization values (87.54% and 30.1%) between them. Based on all these data, it is concluded that strain CRSS-Y-16T represents a novel Streptomyces species, for which the name Streptomyces spinosirectus sp. nov. is proposed. The type strain is CRSS-Y-16T (=MCCC 1K06950T=JCM 35007T).