Aluminum Induces Oxidative Stress Genes in Arabidopsis thaliana1

Abstract

Changes in gene expression induced by toxic levels of Al were characterized to investigate the nature of Al stress. A cDNA library was constructed from Arabidopsis thaliana seedlings treated with Al for 2 h. We identified five cDNA clones that showed a transient induction of their mRNA levels, four cDNA clones that showed a longer induction period, and two down-regulated genes. Expression of the four long-term-induced genes remained at elevated levels for at least 48 h. The genes encoded peroxidase, glutathione-Stransferase, blue copper-binding protein, and a protein homologous to the reticuline:oxygen oxidoreductase enzyme. Three of these genes are known to be induced by oxidative stresses and the fourth is induced by pathogen treatment. Another oxidative stress gene, superoxide dismutase, and a gene for Bowman-Birk protease inhibitor were also induced by Al in A. thaliana. These results suggested that Al treatment of Arabidopsis induces oxidative stress. In confirmation of this hypothesis, three of four genes induced by Al stress in A. thaliana were also shown to be induced by ozone. Our results demonstrate that oxidative stress is an important component of the plant's reaction to toxic levels of Al.

Gene Expression Profiles during the Initial Phase of Salt Stress in Rice

“…These have been reported as inducible by stresses such as high aluminium, fungal infection, and wounding (Cordero et al, 1994;Richards et al, 1998). With the same kinetics, ␤-glucosidases were found that catalyse the hydrolysis of 1,3-␤-D-glucosidic linkages in 1,3-␤-D-glucans.…”

Senescence-Associated Gene Expression during Ozone-Induced Leaf Senescence in Arabidopsis1

“…Two metalbinding proteins, CCH (copper chaperone) and BCB (blue copper-binding protein), are among the genes induced by O 3 . These genes were previously shown to be induced by acute O 3 exposure; BCB was induced within a 3-h exposure to 0.30 L L Ϫ1 O 3 (Richards et al, 1998) and CCH transcript levels increased by 30% after a 30-min exposure to 0.80 L L Ϫ1 O 3 (Himelblau et al, 1998). Metal-binding proteins may play an important role in metal remobilization during senescence.…”

Antioxidative responses of cell suspension cultures of two Coffea arabica varieties to low aluminum levels at pH 5.8

“…It has also been shown that low concentrations of Al are suffi cient to generate ROS and provoke oxidative stress in plants (Richards et al 1998, Yamamoto et al 2002. We have analysed the responses of key antioxidant enzymes that have been previously shown to respond to metal-induced oxidative stress in plants (Gratão et al 2005).…”

“…Al was shown to enhance SOD mRNA levels in the root tips of Arabidopsis (Richards et al 1998), the roots and shoots of rice seedlings (Sharma & Dubey 2007) and the roots of sorghum (Peixoto et al 1999). …”

“…Al induces the expression of genes that have already been characterised in wheat, maize, sugarcane, tobacco and Arabidopsis (Simonovicova et al 2004, Pereira et al 2011. Richards et al (1998) observed high levels of peroxidase (PER) mRNA in A. thaliana exposed to Al during 48 h (50 μm Al 3+ ), and low of glutathione S-transferase (GST) and superoxide dismutase (SOD) mRNAs. In the same study, catalase (CAT) mRNA declined during Al stress.…”