The Arabidopsis gene CAD1 controls programmed cell death in the plant immune system and encodes a protein containing a MACPF domain

• Published in: Plant and cell physiology Vol. 46; no. 6; pp. 902 - 912
• Main Authors: Morita Yamamuro, C.(Hokkaido Univ., Sapporo (Japan)), Tsutsui, T, Sato, M, Yoshioka, H, Tamaoki, M, Ogawa, D, Matsuura, H, Yoshihara, T, Ikeda, A, Uyeda, I, Yamaguchi, J
• Format: Journal Article
• Language: English
• Published: Japan Oxford University Press 01-06-2005; Oxford Publishing Limited (England)
• Subjects: ACIDE SALICYLIQUE; ACIDO SALICILICO; Amino Acid Sequence; APOPTOSE; APOPTOSIS; Apoptosis - genetics; ARABIDOPSIS; Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - immunology; Base Sequence; CFP; clover yellow vein virus; ClYVV; cyan fluorescent protein; DNA, Plant - genetics; Genes, Plant; GFP; green fluorescent protein; GUS; Hypersensitive response; HYPERSENSITIVITY; IMMUNE RESPONSE; Lycopersicon esculentum; MACPF; Membrane attack complex and perforin; Molecular Sequence Data; Mutation; nahG; NONEXPRESSOR OF PR GENES 1; NPR1; pathogenesis-related genes; PCD; PCR; Phenotype; Phylogeny; Plant Diseases - genetics; Plant Diseases - virology; Plant immunity; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - immunology; polymerase chain reaction; PR genes; Programmed cell death; Protein Structure, Tertiary; Pseudomonas syringae; REACCIONES ALERGICAS; REACTION ALLERGIQUE; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; salicylate hydroxylase; Salicylic acid; Salicylic Acid - metabolism; SALICYLIC ACIDS; Sequence Homology, Amino Acid; Signal Transduction; TIR; Toll/interleukin-1 receptor; β-glucuronidase
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pci095

To clarify the processes involved in plant immunity, we have isolated and characterized a single recessive Arabidopsis mutant, cad1 (constitutively activated cell death 1), which shows a phenotype that mimics the lesions seen in the hypersensitive response (HR). This mutant shows spontaneously activated expression of pathogenesis-related (PR) genes, and leading to a 32-fold increase in salicylic acid (SA). Inoculation of cad1 mutant plants with Pseudomonas syringae pv tomato DC3000 shows that the cad1 mutation results in the restriction of bacterial growth. Cloning of CADI reveals that this gene encodes a protein containing a domain with significant homology to the MACPF (membrane attack complex and perforin) domain of complement components and perforin proteins that are involved in innate immunity in animals. Furthermore, cell death is suppressed in transgenic cad1 plants expressing nahG, which encodes an SA-degrading enzyme. We therefore conclude that the CAD1 protein negatively controls the SA-mediated pathway of programmed cell death in plant immunity.