CRISPR Antimicrobial Design for the Control of Bacterial Plant Pathogens

The prokaryotic adaptive immune system, CRISPR, has evolved to target mobile genetic elements, such as phage and plasmids, for destruction in a nucleotide sequence specific manner. Cell death is frequently observed when CRISPR systems are coerced into targeting the bacterial host’s chromosome rather than invading DNA. Building on this capacity for induced autoimmunity, we have developed a CRISPR-based antimicrobial for highly specific bacterial killing. CRISPR antimicrobials are uniquely suited for removing individual strains or genes from complex communities and populations. This feature makes them highly desirable for treatment of bacterial pathogens in situations where broad-spectrum antimicrobials are impractical or undesirable. Plant agriculture in particular, is facing growing consumer rejection of traditional antimicrobial therapies concurrently with an increase in ecological pressures. Bacterial plant pathogens such as Liberibacter, Ralstonia, and Xanthomonas are threatening agricultural systems worldwide and growers need innovative crop protection solutions to manage these diseases. Here we investigate the development potential of CRISPR antimicrobials for mitigation of bacterial disease via direct plant application and treatment of pathogen reservoirs such as soils and irrigation water. We also demonstrate the capacity of CRISPR antimicrobials for target-specific killing with minimal perturbation of plant-associated microbial communities.