Novel commensal rhizobacteria isolated from field-grown canola plants

Plant growth-promoting rhizobacteria have the potential to reduce reliance on synthetic fertilizers. However, the rhizosphere-associated microbiota of canola ( Brassica napus ) remains understudied despite the crop’s global significance. In this study, we isolated and characterized 12 bacterial strains from canola roots, to better understand the diversity and potential agricultural benefits of the canola microbiome. Using a combination of long- and short-read whole-genome sequencing, we generated high-quality genome assemblies of all 12 bacterial species. Genomic analysis revealed genes linked to nitrogen fixation and other potential functional capabilities relevant to plant growth. Growth in nitrogen-deficient media, ammonium production asssays, and acetylene reduction assays, support potential nitrogen fixation traits. Although bacterial inoculation did not significantly enhance early seedling development under nitrogen-limited conditions, continuous coculture with bacteria did not negatively impact plant performance, suggesting a commensal relationship between these isolates and their canola host. This work expands current knowledge of the canola microbiome by identifying commensal microbes closely associated with canola roots for synthetic-community design aimed at improving canola productivity. • Twelve novel rhizobacteria isolated from field-grown canola roots, spanning three phyla. • Closed genomes generated using long- and short-read sequencing, revealing nitrogen fixation and plant-growth traits. • One isolates demonstrated nitrogen fixation • Bacterial growth on canola root exudates did not impair plant development, indicating a commensal relationship.