Abstract
Programmed cell death (PCD) occurs in plants during interactions with and defense to pathogens, designated as plant immunity. Genetic approaches using lesion mimic mutants in Arabidopsis have been used to identify signaling components involved in the plant immunity. We isolated and characterized cad1 (constitutively-activated-cell-death) mutant in Arabidopsis. The cad1 has a single recessive loss-of-function mutation caused by a T-DNA insertion in the CAD1 gene which encodes novel protein with a significant homology to the human Complement and Perforin in MACPF domain. In animals, the MACPF domains have been found to be involved in innate immunity. Furthermore, genetic analysis using npr1-1 and 35S-NahG plants revealed that the CAD1 gene is a novel regulator associated with an alternative pathway of the PCD and defense activation reported previously. Signaling components involved in PCD-mediated plant immunity including the CAD1 and evolutional relationships between plant and animal immunity will be discussed.
