Microvirga rosea sp. nov.: a nanoparticle producing bacterium isolated from soil of rose garden

A Gram-stain negative, aerobic, non-motile, and rod-shaped novel bacterial strain, designated MAH-2^T, was isolated from a soil sample of rose garden and was characterized using a polyphasic approach. The colonies were light pink color, smooth, circular and 0.2-0.6 mm in diameter when grown on nutrient agar for 3 days. Strain MAH-2^T grows at 15-40 °C (optimum growth temperature 30 °C), at pH 5.0-7.0 (optimum growth pH 6.5) and at 0-2% NaCl (optimum 0-0.5%). Cell growth occurs on nutrient agar and R2A agar but not on tryptone soya agar, luria-bertani agar and MacConkey agar. The strain was positive for both catalase and oxidase tests. The strain was able to synthesis of silver nanoparticles. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Microvirga and was most closely related to Microvirga soli R491^T (96.7% sequence similarity), Microvirga subterranea Fail4^T (96.4%), Microvirga guangxiensis 25B^T (96.0%) and Microvirga aerophila 5420S-12^T (95.9%). The genomic DNA G + C content of isolated strain was determined to be 62.5 mol% and the predominant isoprenoid quinone was Q-10. The major fatty acids were identified as summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c) and C_19:0 cyclo ω8c. On the basis of these phenotypic, genotypic, and chemotaxonomic studies and DNA-DNA hybridization results, the isolated strain MAH-2^T represents a novel species, for which the name Microvirga rosea sp. nov. is proposed, with MAH-2^T as the type strain (= KACC 19290^T = CGMCC1.16488^T).