Pseudomonas alliivorans sp. nov., a plant-pathogenic bacterium isolated from onion foliage in Georgia, USA

Abstract

This study provides a taxonomic characterization of three bacterial strains isolated from onion seedlings in Georgia USA. Yellow-colored colonies were isolated, and a diffusible fluorescent pigment was visible under ultraviolet light on King's medium B. Preliminary analysis of the basic phenotype tests and 16S rRNA gene sequence analysis indicated the onion strains were closely related to Pseudomonas viridiflava with the highest similarity to P. viridiflava DSM 6694^T (99.6%). The phylogenomic analyses based on whole genome sequences showed that the onion strains formed a separate monophyletic clade from other species with P. viridiflava as the closest neighbor. When the onion strains and the P. viridiflava type strain were compared, the average nucleotide identity values was 91.6%. Additionally, the digital DNA-DNA hybridization values of the onion strains were 45.8% or less when compared to the type strains of their close relatives, including P. viridiflava. In addition, biochemical, physiological features, and cellular fatty acid compositions were determined for a polyphasic taxonomic analysis. The results supported that the three onion strains represented a novel Pseudomonas species. We propose a new species as Pseudomonas alliivorans sp. nov., with 20GA0068^T (=LMG 32210^T = CFBP 8885^T) as the type strain. The DNA G + C content of the strain 20GA0068^T is 59.1 mol%.