Negatively controls the salicylic acid (SA)-mediated pathway of programmed cell death in plant immunity. Mainly expressed in the vascular system. Constitutively activated HR-like cell death phenotype with endogenous accumulation of high levels of salicylic acid (SA) and constitutively activated defense phenotype against challenge with P.syringae. Dwarf plant with normal cotyledons, but dark brown- or black-colored cell death lesions on the true leaves. Belongs to the complement C6/C7/C8/C9 (TC 1.C.39) family.