Plants defend themselves from invading pathogens by coordinating activity of several plant defense-‐associated genes. Defense-‐Associated Aspartic Protease-‐1 (DAP1) gene of Arabidopsis encodes for an atypical aspartic protease with a putative proteolytic activity. The DAP1 is a negative regulator of plant immunity and the transgenic plants ectopically expressing this genes support pathogen growth and pathogenicity. The Arabidopsis genome has another putative protese that has ~75% homology to DAP1 present in close proximity and therefore was named DAP2. Here, I describe the role of the DAP2 gene in plant defense responses. Two independent knockout dap2 mutants are found to be more susceptible to virulent Pseudomonas syringae pv. tomato (PstDC3000) compared to Col-‐0 wild-‐type (WT) plants. Plants engineered to overexpress the native DAP2 gene through a constitutive promoter are susceptible to pathogen infection. Histochemical analysis performed using the DAP2 promoter driving expression of a reporter gene demonstrates its roles in plant growth, development and during pathogen infection. DAP2 promoter was found to be active in various growth phases including seedlings and flowers. I also describe in this research report the characterization of dap2-‐1, a defense-‐associated mutant of Arabidopsis. The dap2-‐1 mutant displays various growth and development-‐associated phenotypic differences compared to the wild-‐type plants. More importantly, dap2-‐1 mutants are also shown to have gain-‐of-‐function for plant immunity and are more resistant against pathogen infection.
