Pseudomonas canavaninivorans sp. nov., isolated from bean rhizosphere

A novel canavanine-degrading bacterium, strain HB002^T, was isolated from rhizosphere soil of a catch crop field collected from the island of Reichenau in Konstanz, Germany, and characterized by using polyphasic taxonomy. The facultative aerobe, rod-shaped, Gram-stain-negative bacterium was oxidase- and catalase-positive. The isolate was able to grow on canavanine as a sole carbon and nitrogen source. Results of phylogenetic analysis based on 16S rRNA gene sequences revealed highest similarities to Pseudomonas bijieensis (L22-9^T, 99.93 %), Pseudomonas brassicacearum subsp. neoaurantiaca (ATCC 49054^T, 99.76 %), Pseudomonas brassicacearum subsp. brassicacearum (DBK 11^T, 99.63 %), Pseudomonas thivervalensis (DSM 13194^T, 99.51 %), Pseudomonas kilonensis (DSM 13647^T, 99.39 %) and Pseudomonas corrugata (ATCC29736^T, 99.39 %). Marker gene analysis placed the strain in the intrageneric group of Pseudomonas fluorescens, subgroup P. corrugata. In silico DNA-DNA hybridization and average nucleotide identity values were both under the recommended thresholds for species delineation. The predominant fatty acids of strain HB002^T were C_16 : 0, C_17 : 0 cyclo ω7c and C_18 : 1 ω7c. The major respiratory quinone was Q9, followed by Q8 and minor components of Q7 and Q10. Results from the phenotypic characterization showd the strain's inability to hydrolyse gelatin and to assimilate N-acetyl glucosamide and a positive enzymatic activity of acid phosphatase and naphthol-AS-BI phosphohydrolase that distinguish this strain from closely related type strains. Taken together, these results show that strain HB002^T represents a novel species in the genus Pseudomonas, for which the name Pseudomonas canavaninivorans sp. nov. is proposed. The type strain is HB002^T (=DSM 112525^T=LMG 32336^T).