The Effect of TOPorg and TOP Metalloendopeptidases on H2O2 Production and Cell Death during the Hypersensitive Response in Arabidopsis thaliana

Plants have developed a two-stage defense mechanism composed of PTI (PAMPs-triggered immunity), the first stage in which PAMPs (pathogen-associated molecular patterns) are recognized, and ETI (effector-triggered immunity), the second stage in which virulent pathogens that bypass PTI are recognized by their secreted effector proteins. Certain aspects of the immune system are regulated by the phytohormone salicylic acid (SA). My project focused on the hypersensitive response (HR), a phenomenon in which released ROS (reactive oxygen species) can signal cell death to prevent the reproduction and spread of pathogens, in Arabidopsis thaliana. Finding evidence of whether the suspected SABP (SA-binding protein) TOPorg and its suspected homolog TOP play a role in hydrogen peroxide (H2O2) production or cell death during the HR was the purpose of my project. DAB (3-3′ Diaminobenzidine) and Trypan blue staining techniques were used to monitor H2O2 (an ROS) and cell death, respectively, in TOPorg and TOP T-DNA tagged mutant lines. At the end of the project I found evidence that TOPorg and TOP play a role in the HR. In addition to staining techniques, I became more familiar with plasmid minipreparation, electroporation, PCR, and gel electrophoresis over the course of my internship.