RRC ID 6275
Author Yoshida S, Tamaoki M, Ioki M, Ogawa D, Sato Y, Aono M, Kubo A, Saji S, Saji H, Satoh S, Nakajima N.
Title Ethylene and salicylic acid control glutathione biosynthesis in ozone-exposed Arabidopsis thaliana.
Journal Physiol Plant
Abstract Ozone produces reactive oxygen species and induces the synthesis of phytohormones, including ethylene and salicylic acid. These phytohormones act as signal molecules that enhance cell death in response to ozone exposure. However, some studies have shown that ethylene and salicylic acid can instead decrease the magnitude of ozone-induced cell death. Therefore, we studied the defensive roles of ethylene and salicylic acid against ozone. Unlike the wild-type, Col-0, Arabidopsis mutants deficient in ethylene signaling (ein2) or salicylic acid biosynthesis (sid2) generated high levels of superoxide and exhibited visible leaf injury, indicating that ethylene and salicylic acid can reduce ozone damage. Macroarray analysis suggested that the ethylene and salicylic acid defects influenced glutathione (GSH) metabolism. Increases in the reduced form of GSH occurred in Col-0 6 h after ozone exposure, but little GSH was detected in ein2 and sid2 mutants, suggesting that GSH levels were affected by ethylene or salicylic acid signaling. We performed gene expression analysis by real-time polymerase chain reaction using genes involved in GSH metabolism. Induction of gamma-glutamylcysteine synthetase (GSH1), glutathione synthetase (GSH2), and glutathione reductase 1 (GR1) expression occurred normally in Col-0, but at much lower levels in ein2 and sid2. Enzymatic activities of GSH1 and GSH2 in ein2 and sid2 were significantly lower than in Col-0. Moreover, ozone-induced leaf damage observed in ein2 and sid2 was mitigated by artificial elevation of GSH content. Our results suggest that ethylene and salicylic acid protect against ozone-induced leaf injury by increasing de novo biosynthesis of GSH.
Volume 136(3)
Pages 284-98
Published 2009-7-1
DOI 10.1111/j.1399-3054.2009.01220.x
PMID 19453511
MeSH Arabidopsis / drug effects Arabidopsis / genetics Arabidopsis / metabolism* Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism Ethylenes / metabolism* Gene Expression Regulation, Plant Glutathione / biosynthesis* Intramolecular Transferases / genetics Intramolecular Transferases / metabolism Mutation Oligonucleotide Array Sequence Analysis Ozone / pharmacology* Plant Growth Regulators / metabolism* Receptors, Cell Surface / genetics Receptors, Cell Surface / metabolism Salicylic Acid / metabolism*
IF 4.148
Times Cited 54
Arabidopsis / Cultured plant cells, genes pda