Pseudomonas cedrina subsp. fulgida subsp. nov., a fluorescent bacterium isolated from the phyllosphere of grasses; emended description of Pseudomonas cedrina and description of Pseudomonas cedrina subsp. cedrina subsp. nov.

Abstract

The taxonomic position of a group of four strains, isolated from the phyllosphere of grasses, within the species Pseudomonas cedrina was investigated. The isolates formed a separate cluster through ribotyping and MALDI-TOF MS, which could be clearly differentiated from the type strain of P. cedrina. The differences found between the patterns of the type strain of P. cedrina and the novel isolates were more distinct than those between the type strain and recognized species of the genus Pseudomonas, which were phylogenetically related by 16S rRNA gene sequence analysis. Physiological characterization also revealed significant differences between the novel grass isolates and the type strain of P. cedrina. Siderotyping of the pyoverdines revealed identical pyoverdine-isoelectrofocusing patterns for the novel isolates and the type strain of P. cedrina. However, pyoverdine-mediated (59)Fe cross uptake studies indicated differences in the siderotype. In contrast, phylogenetic analysis based on 16S rRNA gene sequence analysis and DNA-DNA hybridization studies (reassociation value 76.4 %) supported the affiliation of the novel isolates to the species P. cedrina. As a consequence of these observations, the splitting of the species P. cedrina into two novel subspecies Pseudomonas cedrina subsp. cedrina subsp. nov. (type strain CFML 96-198(T)=CIP 105541(T)=DSM 17516(T)) and Pseudomonas cedrina subsp. fulgida subsp. nov. (type strain P 515/12(T)=DSM 14938(T)=LMG 21467(T)) is proposed.