The Arabidopsis gene CAD1 controls programmed cell death in the plant immune system and encodes a protein containing a MACPF domain.
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 CAD1 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.
Morita-Yamamuro
Chizuko
C
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Kita-ku N10-W8, Sapporo, 060-0810 Japan.
Tsutsui
Tomokazu
T
Sato
Masanao
M
Yoshioka
Hirofumi
H
Tamaoki
Masanori
M
Ogawa
Daisuke
D
Matsuura
Hideyuki
H
Yoshihara
Teruhiko
T
Ikeda
Akira
A
Uyeda
Ichiro
I
Yamaguchi
Junji
J
D000595:Amino Acid Sequence; D017209:Apoptosis / Q000235:genetics; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D017434:Protein Structure, Tertiary; D020156:Salicylic Acid / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D018744:DNA, Plant; D010940:Plant Proteins; D020156:Salicylic Acid