Isolation and characterization of Pinibacter soli sp. nov., and in silico genome mining of Pinibacter for biosynthetic gene cluster prediction

초록

A Gram-stain-negative, aerobic, rod-shaped, non-motile and non-flagellated novel bacterial strain, designated MAH-24(T), was isolated from the rhizospheric soil of a pine garden. The colonies were observed to be orange-coloured, smooth, spherical and 0.4-0.8 mm in diameter when grown on Reasoner's 2A agar medium for 2 days. Strain MAH-24(T) was found to be able to grow at 10-35 degrees C, at pH 6.0-9.0 and in the presence of 0-1.0% NaCl (w/v). The strain was found to be positive for the catalase and oxidase tests. The strain was positive for hydrolysis of aesculin and L-tyrosine. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Pinibacter and to be closely related to Pinibacter aurantiacus MAH-26(T) (99.2 % sequence similarity). The novel strain MAH-24(T) has a draft genome size of 5918133 bp (13 contigs), annotated with 4613 protein-coding genes, 47 tRNA and three rRNA genes. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MAH-24(T) and the closest type strain P. aurantiacus MAH-26(T) were in the range of 85.3 and 29.9%, respectively. In silico genome mining revealed that both novel strain MAH-24(T) and P. aurantiacus MAH-26(T) have a significant potential for the production of novel natural products in the future. The genomic DNA G+C content was determined to be 41.0 mol%. The predominant isoprenoid quinone was menaquinone-7. The major fatty acids were identified as C-15:0 iso, C-15:1 iso G and C-17:0 iso 3OH. On the basis of dDDH, ANI, genotypic, chemotaxonomic and physiological data, strain MAH-24(T) represents a novel species within the genus Pinibacter, for which the name Pinibacter soli sp. nov. is proposed, with MAH-24(T) (=KACC 19747(T)=CGMCC 1.13659(T)) as the type strain.

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