Pseudomonas endophytica sp. nov., isolated from stem tissue of Solanum tuberosum L. in Spain

8 páginas, 2 tablas y 2 figuras. We, (the authors), acknowledge IDEBIO S. L. and Dr P. García-Benavides and Dr J. L. Palomo for their help and support. M.H.R.B. is the recipient of a JAE-Doc researcher contract from CSIC cofinanced by ERDF. We are grateful to V. Souza-Egipsy from ICA Electron Microscopy Service.A bacterial strain named BSTT44T was isolated in the course of a study of endophytic bacteria occurring in stems and roots of potato growing in a soil from Salamanca, Spain. The 16S rRNA gene sequence had 99.7% identity with respect to that of its closest relative, Pseudomonas psychrophila E-3T, and the next most closely related type strains were those of Pseudomonas fragi, with 99.6% similarity, Pseudomonas deceptionensis, with 99.2% similarity, and Pseudomonas lundensis, with 99.0% similarity; these results indicate that BSTT44T should be classified within the genus Pseudomonas. Analysis of the housekeeping genes rpoB, rpoD and gyrB confirmed its phylogenetic affiliation and showed identities lower than 92% in all cases with respect to the above-mentioned closest relatives. Cells of the strain bore one polar–subpolar flagellum. The respiratory quinone was Q-9.The major fatty acids were C16:0, C18:1v7c and summed feature 3 (C16:1v7c and/or C16:1v6c). The strain was oxidase-, catalase- and urease-positive and the arginine dihydrolase system was present, but tests for nitrate reduction, b-galactosidase production and aesculin hydrolysis were negative. It could grow at 35 8C and at pH 5–9.The DNA G+C content was 60.2 mol%. DNA–DNA hybridization results showed less than 48% relatedness with respect to the type strains of the four most closely related species. Therefore, the combined results of genotypic, phenotypic and chemotaxonomic analyses support the classification of strain BSTT44 into a novel species of the genus Pseudomonas, for which the name Pseudomonas endophytica sp. nov. is proposed. The type strain is BSTT44T (5LMG 28456T5CECT 8691T).Project CSI327A12-2Peer reviewe