Intrasporangium zincisolvens sp. nov., A Novel Actinobacterium Isolated from Rhizosphere Soil.

A novel phosphate-solubilizing and zinc-solubilizing actinobacterium strain YIM S08009 was isolated from rhizosphere soil collected from Pinus yunnanensis in Wuliangshan National Nature Reserve, Pu'er City, Yunnan Province, southwest PR China. Cells of strain YIM S08009 were Gram-stain-positive, non-motile, irregular rods to cocci, and formed yellow and white colonies on nutrient agar. Growth was observed at 10-40 °C (optimum 25-35 °C), pH 6.0-8.5 (optimum 7), and 0-4% (w/v) NaCl (optimum 1%). The cell wall peptidoglycan contained LL-diaminopimelic acid. The whole-cell sugars were mannose, ribose, glucose, and galactose. The predominant menaquinone was MK-8(H). Major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, unknown lipid, and 3 unknown phospholipids. The predominant fatty acids were iso-C, iso-C and iso-C. The DNA G + C content was 72.6%. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM S08009 belonged to genus Intrasporangium, and was most closely related to Intrasporangium flavum MUSC 78, with 99.0% 16S rRNA gene sequence similarity. Strain YIM S08009 shared 90.1% orthologous average nucleotide identity (OrthoANI) and 39.8% digital DNA-DNA hybridization (dDDH) with I. flavum MUSC 78. The genome of strain YIM S08009 contained phosphate-solubilizing genes (SenX3, RegX3, pstSCAB, ugpBAEC, phoA) and zinc-solubilizing genes (znuABC, zupT), and the strain had also demonstrated in vitro phosphorus and zinc solubilization. Based on the genotypic and phenotypic analyses, strain YIM S08009 (= CGMCC 1.60168 = NBRC 116604 = KCTC 59021) represents a novel Intrasporangium species, for which the name Intrasporangium zincisolvens sp. nov. is proposed.