Diversity of bacteria associated with corn roots inoculated with Canadian woodland soils, and description of Pseudomonas aylmerense sp. nov.

• Main Authors: Caetanie F. Tchagang, Renlin Xu, David Overy, Barbara Blackwell, Denise Chabot, Keith Hubbard, Cyr Lézin Doumbou, Eden S.P. Bromfield, James T. Tambong
• Format: Article
• Language: English
• Published: Elsevier 2018-08-01
• Series: Heliyon
• Subjects: Systematics; Microbiology
• Online Access: http://www.sciencedirect.com/science/article/pii/S2405844018336922

Bacteria associated with corn roots inoculated with soils collected from the Canadian woodlands were isolated and characterized. Genus-level identification based on 16S rRNA sequence analysis classified the 161 isolates in 19 genera. The majority (64%) of the isolates were affiliated with the genus Pseudomonas. Further analysis of the Pseudomonas isolates based on BLASTn and rpoD-rpoB-gyrB concatenated gene phylogeny revealed three unique clusters that could not be assigned to known species. This study reports the taxonomic description of one of the distinct lineages represented by two strains (S1E40T and S1E44) with P. lurida LMG 21995T, P. costantinii LMG 22119T, P. palleroniana LMG 23076T, P. simiae CCUG 50988T and P. extremorientalis LMG 19695T as the closest taxa. Both strains showed low ANIm (<90%) and genome-based DNA-DNA hybridization (<50%) values, which unequivocally delineated the new strains from the closest relatives. These findings were supported by multilocus sequence analysis (MLSA) and DNA fingerprinting. In addition, growth characteristics and biochemical tests revealed patterns that differed from the related species. Strains S1E40T and S1E44 are Gram-negative, aerobic, rod-shaped and motile by at least one flagellum; and grew optimally at 30 °C. The predominant polar lipid is phosphatidylethanolamine while the major respiratory quinone is ubiquinone-9. Based on phenotypic and genotypic data presented here, strains S1E40T and S1E44 represent a novel species for which the name Pseudomonas aylmerense sp. nov. is proposed. The type strain is S1E40T (= LMG 30784T = DOAB 703T = HAMI 3696T) with a G + C content of 61.6%.