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Biocontrol of fungal pathogens infecting Cannabis sativa

Carole Balthazar: Université de Moncton

<div><em>Cannabis sativa </em>is an herbaceous plant known worldwide for its narcotic and medicinal uses (marijuana) or as a source of food and fiber (hemp). Along with proposed legislative changes to legalize cannabis in Canada for recreational consumption in 2018, great interest is now rising around organic production of <em>C. sativa</em>. However, yield and quality of <em>C. sativa</em> are affected by different diseases, many of which are caused by fungal pathogens. Biological control could be a viable alternative to the use of chemical pesticides to control fungal pathogens. In this study, a collection of 184 beneficial bacterial strains belonging to two genera (<em>Pseudomonas</em> and <em>Bacillus</em>) were tested in confrontational assays against fourteen pathogenic fungi infecting <em>C. sativa</em> (belonging to <em>Botrytis </em>sp., <em>Sclerotinium </em>sp., <em>Fusarium </em>sp., <em>Alternaria</em> sp., <em>Nigrospora </em>sp. and <em>Phoma </em>sp.). Two <em>Pseudomonas</em> and seven <em>Bacillus </em>strains significantly repressed the growth of most pathogens under study, suggesting wide spectrum inhibitory capabilities. Next-Gen sequencing of the genomes of these nine bacterial strains has recently been completed and comparative genomic analyses are presently underway to characterize the main genetic elements involved in biocontrol. In parallel, these bacterial strains are being further investigated under <em>in planta</em> conditions to validate their biocontrol efficacy.</div>