Due to their inability to produce antibodies, plants use solely innate mechanisms to fight pathogens. Cell surface receptors detect pathogenic patterns (pattern-triggered immunity), and intracellular receptors respond to pathogenic effectors (effector-triggered immunity). FLS2, a pattern-detecting immune receptor in some angiosperms, detects a 22 amino acid sequence (flg22) in bacterial flagellin and initiates an immune response against the potential bacterial pathogen. Our project knocked out the FLS2 gene in tobacco plants using CRISPR/Cas9, a “molecular scissors” bacterial DNA adaptive immune system co-opted by biologists to excise specific genes. The long-term reasoning for this knockout is to use it as a complementation system to transiently express FLS2 from other flowering plants (that may be better at recognizing various pathogens) in tobacco. The goal is to restore the wild-type PTI phenotype and better understand how the plant immune system evolved.