Pseudomonas coleopterorum sp. nov., a cellulase-producing bacterium isolated from the bark beetle Hylesinus fraxini

We isolated a strain coded Esc2AmT during a study focused on the microbial diversity of adult specimens of the bark beetle Hylesinus fraxini. Its 16S rRNA gene sequence had 99.4 % similarity with respect to its closest relative, Pseudomonas rhizosphaerae IH5T. The analysis of partial sequences of the housekeeping genes rpoB, rpoD and gyrB confirmed that strain Esc2AmT formed a cluster with P. rhizosphaerae IH5T clearly separated from the remaining species of the genus Pseudomonas. Strain Esc2AmT had polar flagella and could grow at temperatures from 4 °C to 30 °C. The respiratory quinone was Q9 and the main fatty acids were C16 : 0, C18 : 1ω7c and/or C18 : 1ω6c in summed feature 8 and C16 : 1ω7c and/or C16 : 1ω6c in summed feature 3. DNA–DNA hybridization results showed 51 % relatedness with respect to P. rhizosphaerae IH5T. Oxidase, catalase and urease-positive, the arginine dihydrolase system was present but nitrate reduction and β-galactosidase production were negative. Aesculin hydrolysis was positive. Based on the results from the genotypic, phenotypic and chemotaxonomic analyses, we propose the classification of strain Esc2AmT as representing a novel species of the genus Pseudomonas, for which we propose the name Pseudomonas coleopterorum sp. nov. The type strain is Esc2AmT ( = LMG 28558T = CECT 8695T).