Streptomyces cynarae sp. nov., a novel actinomycete isolated from the leaves of Cynara scolymus L.

Strain HUAS 13-4, a novel endophytic actinobacterium, was isolated from the leaves of Cynara scolymus L. collected from Changde City in China and characterized using a polyphasic approach. Based on 16S rRNA gene sequence analysis, strain HUAS 13-4 shared the highest sequence similarities to Streptomyces leeuwenhoekii C34 (98.90%), Streptomyces harenosi PRKS01-65 (98.83%) and Streptomyces glomeratus LMG 19903 (98.76%). Phylogenetic analysis of 16S rRNA gene sequence indicated that strain HUAS 13-4 was clustered together with Streptomyces bluensis ISP 5564 and Streptomyces cavernae SYSU K10008. Phylogenomic analysis revealed that strain HUAS 13-4 was most closely related to S. glomeratus JCM 9091. However, the average nucleotide identity and the digital DNA-DNA hybridization values between them were less than 96.7% and 70% cut-off points recommended for delineating species. Based on a comprehensive comparison of the genome sequences and phenotypic characteristics between strain HUAS 13-4 and its relative, strain HUAS 13-4 (= MCCC 1K08364 = JCM 35919) should evidently represent a novel Streptomyces species, and the name Streptomyces cynarae sp. nov. is proposed.