Boosting Plant Defenses with CRISPRi:

Scalable and Transmissible Cellular Engineering

The human race is growing fast. The world population is projected to top 10 billion by 2050. One response to the food supply needs of an increasing world population is creating better crop yield through crop survival. Pathogens and pests can cause catastrophic crop loss. Currently there is no widely used synthetic biological mechanism to help plants fight off bacterial pathogens and pests, so the main way large-scale growers protect crops is by using pesticides. We have engineered two possible solutions to address this problem.

In our first project, we have incorporated catalytically dead CAS9 (dCAS9) in conjunction with synthetic gRNAs complementary to pathogenic bacterial genes into a plasmid that naturally conjugates into neighboring bacterial cells. The specificity of the gRNAs will potentially allow us to target specific populations of bacterial pathogens in soil while leaving positive bacterial populations unharmed.

Our second project will provide plants with a sugar-mediated synthetic circuit that boosts a plant’s natural immune system and pesticide-producing capabilities in response to different levels of sugar a plant naturally produces in response to pests. The repression capabilities of dCAS9 will be used to regulate the synthetic circuit promoters that sense high or low sugar levels, reducing metabolic strain.