Streptomyces solicamelliae sp. nov. and Streptomyces solicathayae sp. nov., isolated from the rhizosphere soil of Camellia oleifera and Cathaya argyrophylla.

Abstract

Two novel actinobacteria strains, HUAS MG47^T and HUAS YS2^T, were isolated from the rhizosphere soil of Camellia oleifera and Cathaya argyrophylla collected from Changde City, Hunan Province, China. These two strains could form rectiflexible spore chains consisting of short cylindrical spores with smooth surfaces, suggesting that they had typical characteristics of the genus Streptomyces. The cell wall peptidoglycan contained ll-diaminopimelic acid as a diagnostic amino acid. The predominant menaquinones were MK-9 (H₆), MK-9 (H₈) and MK-9 (H₄). The genome sizes of HUAS MG47^T and HUAS YS2^T were 7.35 and 7.88 Mbp with a G+C content of 72.3 and 72.0 mol%, respectively. Phylogenetic analysis based on the 16S rRNA gene and five housekeeping gene sequences (atpD, gyrB, recA, rpoB and trpB) indicated that strains HUAS MG47^T and HUAS YS2^T formed an evolutionary lineage with Streptomyces tritici CGMCC 4.7393^T. However, the values of multilocus sequence analysis evolutionary distance, average nucleotide identity and DNA-DNA hybridization between these two strains and their closely related relatives indicated that they were clearly different from other known Streptomyces species. Consequently, based on the polyphasic taxonomic study, HUAS MG47^T and HUAS YS2^T represent two novel Streptomyces species for which the names Streptomyces solicamelliae sp. nov. (HUAS MG47^T=MCCC 1K09365^T=JCM 37293^T) and Streptomyces solicathayae sp. nov. (HUAS YS2^T=MCCC 1K08940^T=JCM 36737^T) are proposed, respectively.