Negative regulator of cell death and defense responses. Exhibits calcium-dependent phospholipid binding properties. Interacts with BON1 (via VWA domain), BON2 and BON3. A number of isoforms are produced. According to EST sequences. Expressed in roots, leaves, stems and flowers. Down-regulated by high temperature. Up-regulated by salicylic acid, AgNO(3), chitin, cycloheximide, ozone, syringolin, salt stress and upon pathogen or nematode infection. Dwarf, twisted leaves and enhanced disease resistance to bacterial and oomycete pathogens in cv. Columbia when grown under constant loght at 22 degrees Celsius. No visible phenotype when grown at 28 degrees Celsius. Accelerated hypersensitive response (HR). Bap1 and bap2 double mutant is seedling lethal. Overexpression of BAP1 can suppress a defect in BON1 and confers more susceptibility to virulent pathogens. Truncated N-terminus. Truncated N-terminus.