Pseudomonas canadensis sp. nov. a biological control agent isolated from a field plot under long-term mineral fertilization

摘要

The bacterial strain 2-92^T, isolated from a field plot under long-term (>40 years) mineral fertilization, exhibited in vitro antagonistic properties against fungal pathogens. A polyphasic approach was undertaken to verify its taxonomic status. Strain 2-92^T was Gram-reaction-negative, aerobic, non-spore-forming, motile by one or more flagella, and oxidase-, catalase- and urease-positive. The optimal growth temperature of strain 2-92^T was 30 °C. 16S rRNA gene sequence analysis demonstrated that the strain is related to species of the genus . Phylogenetic analysis of six housekeeping genes (dnaA, gyrB, recA, recF, rpoB and rpoD) revealed that strain 2-92^T clustered as a distinct and well separated lineage with Pseudomonas as the most closely related species. Polar lipid and fatty acid compositions corroborated the taxonomic position of strain 2-92^T in the genus . Phenotypic characteristics from carbon utilization tests could be used to differentiate strain 2-92^T from closely related species of the genus . DNA–DNA hybridization values (wet laboratory and genome-based) and average nucleotide identity data confirmed that this strain represents a novel species. On the basis of phenotypic and genotypic characteristics, it is concluded that this strain represents a separate novel species for which the name Pseudomonas canadensis sp. nov. is proposed, with type strain 2-92^T (=LMG 28499^T=DOAB 798^T). The DNA G+C content is 60.30 mol%.