Cb. Xiang et Dj. Oliver, GLUTATHIONE METABOLIC GENES COORDINATELY RESPOND TO HEAVY-METALS AND JASMONIC ACID IN ARABIDOPSIS, The Plant cell, 10(9), 1998, pp. 1539-1550
Glutathione plays a pivotal role in protecting plants from environment
al stresses, oxidative stress, xenobiotics, and some heavy metals. Ara
bidopsis plants treated with cadmium or copper responded by increasing
transcription of the genes for glutathione synthesis, gamma-glutamylc
ysteine synthetase and glutathione synthetase, as well as glutathione
reductase. The response was specific for those metals whose toxicity i
s thought to be mitigated through phytochelatins, and other toxic and
nontoxic metals did not alter mRNA levels. Feeding experiments suggest
ed that neither oxidative stress, as results from exposure to H2O2, no
r oxidized or reduced glutathione levels were responsible for activati
ng transcription of these genes. Jasmonic acid also activated the same
suite of genes, which suggests that it might be involved in the signa
l transduction pathway for copper and cadmium. Jasmonic acid treatment
increased mRNA levels and the capacity for glutathione synthesis but
did not alter the glutathione content in unstressed plants, which supp
orts the idea that the glutathione concentration is controlled at mult
iple levels.