Abstract
To clarify the plant defense mechanisms, we isolated and characterized a single recessive T-DNA tagged Arabidopsis mutant, cad1 (constitutively activated cell death), which shows spontaneously activated PR (pathogenesis-related) genes expression and cell death in vascular bundle. CAD1 gene encodes a protein with a significant homology to the Complement and Perforin in MACPF (Membrane attack complex and Perforin) domain, is a member of uncharacterized gene family in higher plant. MACPF domains have been identified in many animal species, and to be involved in innate immunity. Expression of the CAD1 gene was observed at vascular bundle of developing leaves and roots. Furthermore, genetic analysis using npr1-1 (nonexpresser of PR gene) and 35S-NahG plants revealed that the CAD1 gene regulate a novel pathway of cell death and defense activation in Arabidopsis.
