Topp, Stephanie2008-08-012013-08-012008-08-01bibid: 6397242https://hdl.handle.net/1813/11205In modern agriculture, a great deal of time and resources are spent combating widespread insect infestation and microbial infections. Comprehension of the natural defenses against these threats could enable the production of genetically modified plants with enhanced innate immunity without the use of chemicals to which insects and microbes are renown for developing resistances to. Plants have three main defense mechanisms to guard against bacteria: physical tissue barriers, basal defenses, and race-specific resistance. In the latter case, the plant cell perceives foreign proteins and this triggers the hypersensitive response (HR), a programmed cell death (PCD) to prevent further spread of the pathogen. This is mediated by the recognition of specific avirulence (Avr) proteins from the pathogen by resistance (R) proteins in the plant. A member of the evolutionarily conserved copine family, BONZAI 1 (BON 1) is a key regulator of defense responses in A. thaliana. BON1 has been shown to negatively regulate the R gene suppressor of npr1-1, constitutive 1 (SNC1). In the Columbia (Col) accession of A. thaliana, the loss-of-function (LOF) bon1-1 mutant allele exhibits a growth defect phenotype (dwarfed plant). bon1-1 leads to constitutive activation of SNC1 which compromises normal plant growth. BON1 has been shown to interact with two other proteins: BON1-associated protein 1 and 2 (BAP1, BAP2). The molecular link(s) between BON1 and BAP, and their negative regulation of plant defenses are not well understood. We report the identification and characterization of a new component in the BON1 regulatory pathway and our efforts in probing the biochemical activities of BAP2 in regulating defense responses.endefense regulation, BON1, BAP2dissertation or thesis