Mechanism of gene expression of Arabidopsis glutathione S-transferase, AtGST1, and AtGST11 in response to aluminum stress.
The gene expression of two Al-induced Arabidopsis glutathione S-transferase genes, AtGST1 and AtGST11, was analyzed to investigate the mechanism underlying the response to Al stress. An approximately 1-kb DNA fragment of the 5'-upstream region of each gene was fused to a beta-glucuronidase (GUS) reporter gene (pAtGST1::GUS and pAtGST11::GUS) and introduced into Arabidopsis ecotype Landsberg erecta. The constructed transgenic lines showed a time-dependent gene expression to a different degree in the root and/or leaf by Al stress. The pAtGST1::GUS gene was induced after a short Al treatment (maximum expression after a 2-h exposure), while the pAtGST11::GUS gene was induced by a longer Al treatment (approximately 8 h for maximum expression). Since the gene expression was observed in the leaf when only the root was exposed to Al stress, a signaling system between the root and shoot was suggested in Al stress. A GUS staining experiment using an adult transgenic line carrying the pAtGST11::GUS gene supported this suggestion. Furthermore, Al treatment simultaneously with various Ca depleted conditions in root region enhanced the gene expression of the pAtGST11::GUS in the shoot region. This result suggested that the degree of Al toxicity in the root reflects the gene response of pAtGST11::GUS in the shoot via the deduced signaling system. Both transgenic lines also showed an increase of GUS activity after cold stress, heat stress, metal toxicity, and oxidative damages, suggesting a common induction mechanism in response to the tested stresses including Al stress.
Ezaki
Bunichi
B
Research Institute for Bioresources, Okayama University, 2-20-1, Chuou, Kurashiki, Okayama 710-0046, Japan. bezaki@rib.okayama-u.ac.jp
Suzuki
Masakatsu
M
Motoda
Hirotoshi
H
Kawamura
Masako
M
Nakashima
Susumu
S
Matsumoto
Hideaki
H
D000222:Adaptation, Physiological / Q000187:drug effects*; D000535:Aluminum / Q000633:toxicity*; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D018520:Plant Shoots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
D000535:Aluminum; D029681:Arabidopsis Proteins; D002118:Calcium; D005966:Glucuronidase; D005982:Glutathione Transferase; C488504:GST11 protein, Arabidopsis; C478067:At1g02930 protein, Arabidopsis