Streptomyces xingningensis sp. nov. and Streptomyces rhizosphaerae sp. nov. isolated from the rhizosphere soil of Camellia oleifera.

Two novel actinobacteria strains, designated YCB024T and YCB041T, were isolated from rhizosphere soil samples of Camellia oleifera collected from Xingning City, Guangdong Province, PR China. Both strains exhibited mycelial filaments and intertwined hyphal cells. Phylogenetic analysis revealed that strain YCB024T exhibited the highest 98.8% 16S rRNA gene similarity with Streptomyces yogyakartensis NBRC 100779T, Streptomyces javensis NBRC 100777T and Streptomyces violaceusniger NBRC 13459T, and strain YCB041T exhibited the highest 98.9% similarity with Streptomyces albospinus NBRC 13846T. The average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values among the two strains and their closely related species indicated that they were clearly different from other known Streptomyces species. The draft genome sizes of the two strains were 6.9 Mbp and 9.5 Mbp with DNA G+C contents of 70.4 mol% and 71.7 mol%. The major cellular fatty acids in strain YCB024T included iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0, and strain YCB041T included iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0. The major polar lipids of the two strains were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside or unidentified aminophospholipid. The respiratory quinones of both strains included MK-9 (H6), MK-9 (H8) and MK-10 (H4). Based on phylogenetic analysis, ANI and dDDH values, physiological and chemical properties, strains YCB024T and YCB041T represent two novel species of the genus Streptomyces, for which the names Streptomyces xingningensis sp. nov. (type strain YCB024T=GDMCC 4.314T=JCM 36249T) and Streptomyces rhizosphaerae sp. nov. (type strain YCB041T=GDMCC 4.469T=JCM 38170T) are proposed, respectively.