Isolation and characterisation of virulent bacteriophage targeting canola rhizosphere bacteria Klebsiella grimontii and Bacillus sp.

Rhizosphere bacteria can have a range of impacts on their plant host. Bacteriophage, viruses which specifically infect and kill bacteria, shape diverse microbial communities by lysing beneficial, commensal and pathogenic bacterial species. Phage mediated bacterial lysis could therefore be deployed to target bacterial species in the rhizosphere to suppress disease without reducing the positive effects of other bacterial communities on the host plant. Here we isolated, sequenced, and characterized four virulent bacteriophage that target two Canola-root associated bacterial isolates, Klebsiella grimontii and Bacillus sp. Genomic and biological analysis showed all four phages are strictly lytic with no lysogenic markers, antibiotic resistance genes or virulence factors. Phylogenetic analysis placed Klebsiella phage KOB, KOH and KOR as strains of a single new species within the Reminisvirus genus, and Bacillus phage BW01 as a species within the proposed genus Zaviarvirus. These findings expand our knowledge of phage diversity in the rhizosphere and provide a foundation for understanding their roles in synthetic and natural communities.