Salicylic acid-mediated cell death in the Arabidopsis len3 mutant.
The Arabidopsis lesion initiation 3 (len3) mutant develops lesions on leaves without pathogen attack. len3 plants exhibit stunted growth, constitutively express pathogenesis-related (PR) genes, PR-1, PR-2, and PR-5, and accumulate elevated levels of salicylic acid (SA). Furthermore, len3 is a semidominant, male gametophytic lethal mutation with partial defects in female gametophytic development. To determine the signaling pathway activated in len3 plants, we crossed the len3 plants with nahG, npr1-1, and pad4-1 plants and analyzed the phenotypes of the double mutants. The len3-conferred phenotypes, including cell death and PR-1 expressions, were suppressed in the double mutants. Thus SA, NPR1, and PAD4 are required for the phenotypes. However, none of these double mutants could completely suppress the len3-conferred stunted growth. This result suggests that an SA-, NPR1-, and PAD4-independent pathway is also involved in the phenotype. Treatment with BTH (benzo(1,2,3)thiadiazole-7-carbothioic acid), an SA analog, induced cell death in len3 nahG plants but not in len3 npr1 or len3 pad4 plants, suggesting the involvement of the PAD4-dependent but SA-independent second signal pathway in cell death in len3 plants.
Ishikawa
Atsushi
A
Department of Bioscience, Fukui Prefectural University. ishikawa@fpu.ac.jp
Kimura
Yuri
Y
Yasuda
Michiko
M
Nakashita
Hideo
H
Yoshida
Shigeo
S
D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002264:Carboxylic Acids / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D020156:Salicylic Acid / Q000378:metabolism / Q000494:pharmacology*; D013830:Thiadiazoles / Q000494:pharmacology
D029681:Arabidopsis Proteins; D002264:Carboxylic Acids; C105496:NPR1 protein, Arabidopsis; D010940:Plant Proteins; D013830:Thiadiazoles; C433224:benzo(1,2,3)-thiadiazole-7-carboxylic acid; C053376:pathogenesis-related proteins, plant; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis; D020156:Salicylic Acid